LU-7059 mdt: reset rc=0 in mdt_lock_objects_in_linkea

LU-7059 mdt: reset rc=0 in mdt_lock_objects_in_linkea

reset rc to 0 in mdt_lock_objects_in_linkea, otherwise
it might cause migration failure for mulitple link file.

Add sanity.sh 230e to verify the case.

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I063a6e461e2fe427105e8063720f59df42a8eda3
Reviewed-on: http://review.whamcloud.com/16131
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>