LU-6235 scrub: replace the stale OI mapping

LU-6235 scrub: replace the stale OI mapping

If the OI mapping on the OST contains an invalid one, then the OI
lookup via osd_obj_map_lookup() may return -ENOENT. From the view
of OI scrub, it is indistinguishable from the case of there is no
such OI mapping, then it will cause the OI scrub to use "INSERT"
@ops for osd_scrub_refresh_mapping() to repair such inconsistency
by wrong. So the osd_obj_map_lookup() should return -ESTALE under
the case of invalid OI mapping exists, then the OI scrub can use
"UPDATE" @ops for osd_scrub_refresh_mapping() to repair.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I013125eb0aaec683ac8f56ec32a30e7858262f87
Reviewed-on: http://review.whamcloud.com/13745
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>