LU-5513 lfsck: repair multiple referenced name entry

LU-5513 lfsck: repair multiple referenced name entry

If more than one MDT-objects back reference the same name entry via
their each own linkEA entry, but the name entry only references one
MDT-object of them. Then for those non-recognized MDT-objects, the
namespace LFSCK will remove the non-recognized linkEA entries when
double scan them. And if the MDT-object has no linkEA entries left
after the cleanup, then it will be regarded as orphan and inserted
into .lustre/lost+found/MDTxxxx/ directory with the name:
${FID}-${infix}-${type}-${conflict_version}

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ie50711c3c17861bd2c0f491052caa9dcea0e02f2
Reviewed-on: http://review.whamcloud.com/12247
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Andreas Dilger <andreas.dilger@intel.com>