LU-3039 lfsck: misc patch for LFSCK 1.5 debts (1)

LU-3039 lfsck: misc patch for LFSCK 1.5 debts (1)

1) Handle backup and restore case: add FID-in-dirent by re-insert
   the name entry with proper ldiskfs PDO lock processed.

2) Fix some deadlock cases between LFSCK engine thread and OI scrub
   thread: one may fall into wait without waking up the other.

3) lfsck performance test for the cases: lfsck with load, lfsck
   during create, backup/restore, simulate upgrade from 1.8.

4) Other cleanup.

Test-Parameters: testlist=sanity-scrub,sanity-lfsck,lfsck-performance

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ib539291c604d807475cacfdd56d910e9e86d6ac7
Reviewed-on: http://review.whamcloud.com/5764
Tested-by: Hudson
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>