Fix bug that causes _find_all_fs to find only one filesystem.

Modified _match_mdtstat to compare both the numeric portion of
the target name and the filesystem name.  With this change,
mdt records with the same numeric identifier, but for different
filesystems, get separate entries in the mdt_data list.
_find_all_fs builds its list fsl from the mdtstat_m.fsname
field of each mdt_data list element.