This patch makes the layout LFSCK to support mirrored file
as following:

1. Verify mirrored file's LOV EA and PFID EA, including all
   kinds of inconsistencies as non-mirrored file may hit.

2. Rebuild mirrored file's LOV EA from orphan OST-objects,
   recover the component's status/flags before the crash:
   init, stale, and so on.

3. For the mirrored file with dangling reference (OST object),
   it does NOT rebuild the lost OST-object from other replica,
   instead, it either reports the curruption or re-create empty
   OST-object that follows the same rules as non-mirrored case.

Some code cleanup and new test cases for LFSCK against mirrored file.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I560746fc2aae40101dcb0e8513b6c7ed54902ec6
Reviewed-on: https://review.whamcloud.com/32705


Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>