LU-9086 gss: handle specific mgc binding

LU-9086 gss: handle specific mgc binding

Recent work has made mgc config log handle more than one MGC
existing on a client node which is the case when more than
one lustre file system is mounted. This broke sptlrpc
handling due to cfg_instance no longer being NULL. Since
this is the case we remove the cfg_instance NULL test in
class_config_llog_handler.

The second problem exposed was due to cfg_obdname changing from
the file system name to the actual mgc abstract client device.
Since target2fsname() was only checking fsname-[MDT|OST]XXXX we
could use this function with the obd_uuid field which has the
format of fsname-[MDT|OST]XXXX_UUID. For the case of obd names
with the format fsname-XXXXXXX those obd device have an obd_uuid
that is just some random long hexadecimal string. To handle the
obd_uuid case use the proper obd_uuid2fsname() function instead
of target2fsname(). Rename target2fsname() to obdname2fsname()
since this what it now does. Add handling the fsname-XXXXXXXX
obd name format to obdname2fsname().

Change-Id: I6c3235b3e2d41ef955b98d30aec76d47346c2369
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/25959
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>