Fix busy detection of file systems inside Linux Software RAID (#712533)

On some distributions GParted doesn't detect when a file system is busy
and mounted when the partition is within a Linux Software RAID array.
Affected distributions include: Debian 6, Debian 7 and RHEL/CentOS 6.x.

This is because of a bug in libparted 2.3 and earlier.  It was fixed by
this change in libparted 2.4:
    http://git.savannah.gnu.org/cgit/parted.git/commit/?id=db52898c214310dab4ed84e6cb2f9ffc8c3aa502
    linux: also detect "in-use" dmraid and scsi-Nth (N>=16) partition

Ubuntu 13.10 with libparted 2.3 is not affected because it contains a
distribution specific patch to correct it.

Fix by using GParted's internal mounted partitions map, mount_info, to
determine if a partition is busy, in addition to using libparted's
ped_partition_is_busy().

Bug #712533 - Partitions not detected as busy inside Software RAID on
              some distros

src/GParted_Core.cc

@@ -1051,10 +1051,21 @@ void GParted_Core::set_device_partitions( Device & device, PedDevice* lp_device,
 				}
 				else
 #endif
-					partition_is_busy =    ped_partition_is_busy( lp_partition )
+				{
-					                    || ( filesystem == FS_LVM2_PV      && lvm2_pv_info .has_active_lvs( partition_path ) )
+					//Determine if partition is busy:
+					//  1st search GParted internal mounted partitions map;
+					//  2nd custom checks for none file system partitions;
+					//  3rd use libparted.
+					iter_mp = mount_info .find( partition_path ) ;
+					if ( iter_mp != mount_info .end() )
+						partition_is_busy = true ;
+
+					partition_is_busy |=    ( filesystem == FS_LVM2_PV      && lvm2_pv_info .has_active_lvs( partition_path ) )
 					                     || ( filesystem == FS_LINUX_SWRAID && Utils::swraid_member_is_active( partition_path ) ) ;
 
+					partition_is_busy |= ped_partition_is_busy( lp_partition ) ;
+				}
+
 				partition_temp .Set( device .get_path(),
 						     partition_path,
 						     lp_partition ->num,
@@ -1095,7 +1106,10 @@ void GParted_Core::set_device_partitions( Device & device, PedDevice* lp_device,
 				}
 				else
 #endif
+				{
+					//For extended partitions only use libparted to determine if it's busy.
 					partition_is_busy = ped_partition_is_busy( lp_partition ) ;
+				}
 
 				partition_temp .Set( device .get_path(),
 						     partition_path,