Fix long scan problem when BIOS floppy setting incorrect

The call to "blkid -c /dev/null" on Precise Pangolin Alpha 1 takes
exceedingly long.  This occurs when the BIOS is incorrectly set to
indicate a floppy drive is present when none is physically installed. 
Use cached blkid results instead.

Ubuntu launchpad 910379 - Gparted does not start and continues to
                          scan devices
https://bugs.launchpad.net/ubuntu/+source/gparted/+bug/910379

src/FS_Info.cc

@@ -61,7 +61,7 @@ void FS_Info::load_fs_info_cache()
 	Glib::ustring output, error ;
 	if ( blkid_found )
 	{
-		if ( ! Utils::execute_command( "blkid -c /dev/null", output, error, true ) )
+		if ( ! Utils::execute_command( "blkid", output, error, true ) )
 			fs_info_cache = output ;
 		else
 			fs_info_cache = "" ;