LU-8218 osd: handle stale OI mapping for non-restore case

LU-8218 osd: handle stale OI mapping for non-restore case

Sometimes, the user may removes the MDT-object under ldiskfs mode
directly but leaves related OI mapping there. Such case also can
happen if the MDT-object lost because of disk corruption. Under
such case, the OSD ldiskfs should has the ability to distinguish
it from the case of MDT file-level backup/restore; otherwise, the
up layer user will get -EREMCHG (78) when locating such MDT-object
with the FID.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Iede2542968c21755158637089d20a694f12b309e
Reviewed-on: http://review.whamcloud.com/20659
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>