Stop assigning a zero length string when constructing them

Most of the code doesn't assign a zero length string when constructing a
string object.  However there were a few places where it did.  This is
unnecessary because Glib::ustring [1] and std::string [2] objects are
constructed as the the empty string by default.

[1] Glib::ustring::ustring()
    https://developer-old.gnome.org/glibmm/stable/classGlib_1_1ustring.html#a71802782f4c2c408ef7ac69c6564b370
        "Glib::ustring::ustring()
        Default constructor, which creates an empty string.
        "
[2] std::string::string
    https://cplusplus.com/reference/string/string/string/
        "(1) empty string constructor (default constructor)
        Constructs an empty string, with a length of zero characters.
        "

src/DMRaid.cc

@@ -210,12 +210,11 @@ void DMRaid::get_devices( std::vector<Glib::ustring> & device_list )
 Glib::ustring DMRaid::get_dmraid_name( const Glib::ustring & dev_path )
 {
 	//Retrieve name of dmraid device
-	Glib::ustring dmraid_name = "" ;
+	Glib::ustring dmraid_name;
-	Glib::ustring regexp = "" ;
 
 	for ( unsigned int k=0; k < dmraid_devices .size(); k++ )
 	{
-		regexp = ".*(" + dmraid_devices[k] + ").*" ;
+		Glib::ustring regexp = ".*(" + dmraid_devices[k] + ").*";
 		if ( Utils::regexp_label( dev_path, regexp ) == dmraid_devices[k] )
 			dmraid_name = dmraid_devices[k] ;
 	}
@@ -256,7 +255,7 @@ void DMRaid::get_dmraid_dir_entries( const Glib::ustring & dev_path, std::vector
 	Glib::ustring dmraid_name = get_dmraid_name( dev_path ) ;
 
 	//Loop through the entries in the directory
-	Glib::ustring filename = "" ;
+	Glib::ustring filename;
 	Glib::Dir dir( DEV_MAPPER_PATH );
 	while ( ( filename = dir .read_name() ) != "" )
 	{
@@ -277,9 +276,9 @@ int DMRaid::get_partition_number( const Glib::ustring & partition_name )
 Glib::ustring DMRaid::get_udev_dm_name( const Glib::ustring & dev_path )
 {
 	//Retrieve DM_NAME of device using udev information
-	Glib::ustring output = "" ;
+	Glib::ustring output;
-	Glib::ustring error  = "" ;
+	Glib::ustring error;
-	Glib::ustring dm_name = "" ;
+	Glib::ustring dm_name;
 
 	if (udevadm_found)
 		Utils::execute_command( "udevadm info --query=all --name=" + Glib::shell_quote( dev_path ),

src/Dialog_Partition_Info.cc

@@ -228,7 +228,7 @@ void Dialog_Partition_Info::Display_Info()
 
 	Sector ptn_sectors = partition .get_sector_length() ;
 
-	Glib::ustring vgname = "" ;  //Also used in partition status message
+	Glib::ustring vgname;
 	if (filesystem_ptn.fstype == FS_LVM2_PV)
 		vgname = LVM2_PV_Info::get_vg_name( filesystem_ptn.get_path() );
 

src/GParted_Core.cc

@@ -1235,7 +1235,6 @@ FSType GParted_Core::detect_filesystem(const PedDevice *lp_device, const PedPart
 {
 	g_assert(lp_device != nullptr);  // Bug: Not initialised by call to ped_device_get() or ped_device_get_next()
 
-	Glib::ustring fsname = "";
 	Glib::ustring path;
 	DMRaid dmraid;
 
@@ -1257,7 +1256,7 @@ FSType GParted_Core::detect_filesystem(const PedDevice *lp_device, const PedPart
 	// (Q2) FS_Info (blkid) file system detection
 	// Blkid detects more signatures and generally has less limitations so use before
 	// libparted detection, but it doesn't report anything for extended partitions.
-	fsname = FS_Info::get_fs_type( path );
+	Glib::ustring fsname = FS_Info::get_fs_type(path);
 
 	// (Q3) Libparted file system detection
 	// Only used when blkid didn't report anything and only on partitions, not whole

src/Win_GParted.cc

@@ -3322,7 +3322,7 @@ void Win_GParted::activate_change_uuid()
 		                           Gtk::MESSAGE_WARNING,
 		                           Gtk::BUTTONS_OK,
 		                           true );
-		Glib::ustring tmp_msg = "" ;
+		Glib::ustring tmp_msg;
 		for ( i = 1 ; filesystem_object->get_custom_text( CTEXT_CHANGE_UUID_WARNING, i ) != "" ; i++ )
 		{
 			if ( i > 1 )
@@ -3564,7 +3564,7 @@ bool Win_GParted::remove_non_empty_lvm2_pv_dialog( const OperationType optype )
 	                                            true, false, false, Gtk::ALIGN_START);
 	grid->attach(*label_members, 0, 1, 1, 1);
 
-	Glib::ustring members_str = "" ;
+	Glib::ustring members_str;
 	if ( ! members .empty() )
 	{
 		for ( unsigned int i = 0 ; i < members .size() ; i ++ )

src/f2fs.cc

@@ -128,7 +128,7 @@ bool f2fs::create( const Partition & new_partition, OperationDetail & operationd
 
 bool f2fs::resize(const Partition & partition_new, OperationDetail & operationdetail, bool fill_partition)
 {
-	Glib::ustring size = "";
+	Glib::ustring size;
 	if (! fill_partition)
 		// resize.f2fs works in sector size units of whatever device the file
 		// system is currently stored on.

src/fat16.cc

@@ -209,7 +209,7 @@ void fat16::read_label(Partition& partition)
 
 bool fat16::write_label( const Partition & partition, OperationDetail & operationdetail )
 {
-	Glib::ustring cmd = "" ;
+	Glib::ustring cmd;
 	if ( partition.get_filesystem_label().empty() )
 		cmd = "mlabel -c -i " + Glib::shell_quote(partition.get_path()) + " ::";
 	else

src/hfs.cc

@@ -57,7 +57,7 @@ FS hfs::get_filesystem_support()
 
 bool hfs::create( const Partition & new_partition, OperationDetail & operationdetail )
 {
-	Glib::ustring cmd = "";
+	Glib::ustring cmd;
 	if( new_partition.get_filesystem_label().empty() )
 		cmd = "hformat " + Glib::shell_quote( new_partition.get_path() );
 	else

src/hfsplus.cc

@@ -55,7 +55,7 @@ FS hfsplus::get_filesystem_support()
 
 bool hfsplus::create( const Partition & new_partition, OperationDetail & operationdetail )
 {
-	Glib::ustring cmd = "";
+	Glib::ustring cmd;
 	if( new_partition.get_filesystem_label().empty() )
 		cmd = "mkfs.hfsplus " + Glib::shell_quote( new_partition.get_path() );
 	else

src/luks.cc

@@ -151,7 +151,7 @@ bool luks::resize( const Partition & partition_new, OperationDetail & operationd
 		}
 	}
 
-	Glib::ustring size = "";
+	Glib::ustring size;
 	if ( ! fill_partition )
 		// Cryptsetup resize takes the size of the encryption mapping, not the
 		// size of the underlying block device.  Both device-mapper and cryptsetup

src/lvm2_pv.cc

@@ -105,7 +105,7 @@ bool lvm2_pv::create( const Partition & new_partition, OperationDetail & operati
 
 bool lvm2_pv::resize( const Partition & partition_new, OperationDetail & operationdetail, bool fill_partition )
 {
-	Glib::ustring size = "" ;
+	Glib::ustring size;
 	if ( ! fill_partition )
 		size = " --yes --setphysicalvolumesize " +
 		       Utils::num_to_str(partition_new.get_byte_length() / KIBIBYTE) + "K ";

src/ntfs.cc

@@ -190,7 +190,7 @@ bool ntfs::create( const Partition & new_partition, OperationDetail & operationd
 bool ntfs::resize( const Partition & partition_new, OperationDetail & operationdetail, bool fill_partition )
 {
 	bool success;
-	Glib::ustring size = "" ;
+	Glib::ustring size;
 	if ( ! fill_partition )
 		size = " -s " + Utils::num_to_str(partition_new.get_byte_length());
 	Glib::ustring cmd = "ntfsresize --force --force" + size ;

src/reiserfs.cc

@@ -176,7 +176,7 @@ bool reiserfs::create( const Partition & new_partition, OperationDetail & operat
 
 bool reiserfs::resize( const Partition & partition_new, OperationDetail & operationdetail, bool fill_partition )
 { 
-	Glib::ustring size = "" ;
+	Glib::ustring size;
 	if ( ! fill_partition )
 		size = " -s " + Utils::num_to_str(partition_new.get_byte_length());
 	const Glib::ustring resize_cmd = "echo y | resize_reiserfs" + size +