LU-5519 lfsck: LFSCK code framework adjustment (2)

LU-5519 lfsck: LFSCK code framework adjustment (2)

Enhance LFSCK code framework for striped directory verification,
including:

1) New lfsck component APIs: lfsck_operations::lfsck_open_dir()
   and lfsck_operations::lfsck_close_dir().
1.1) The namespace LFSCK uses lfsck_open_dir() to initialize the
     LMV EA verification environment.
1.2) The namespace LFSCK uses lfsck_close_dir() to indicate the
     end of the scanning the striped directory.

2) When create orphan parent, the LMV EA should be considered.

3) Data structure definition and extention.

4) Other code cleanup.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I01e14645796c3fa3269c5f3cdcbb755ccb455d7e
Reviewed-on: http://review.whamcloud.com/11845
Tested-by: Jenkins
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>