LU-6895 scrub: not trigger scrub if inode removed by race

LU-6895 scrub: not trigger scrub if inode removed by race

When osd_consistency_check(), the target file may has just been
removed by other, so the osd_oi_lookup() will return -ENOENT to
the caller. Under such case, the osd_consistency_check() should
not trigger OI scrub.

On the other hand, if someone unlinked the file during OI scrub
adding the missed OI mapping to the OI file, the OI scrub needs
to remove the new added OI mapping.

Test-Parameters: alwaysuploadlogs \
envdefinitions=SLOW=yes,ENABLE_QUOTA=yes \
mdtfilesystemtype=ldiskfs mdsfilesystemtype=ldiskfs \
ostfilesystemtype=ldiskfs clientdistro=el7 ossdistro=el7 \
mdsdistro=el7 mdtcount=1 \
testlist=sanity-scrub,sanity-scrub,sanity-scrub,sanity-scrub

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I4703fc7f99d7b0a0f769127b5cdba5a2b992250d
Reviewed-on: http://review.whamcloud.com/16439
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>