After landing patch https://review.whamcloud.com/32959/ "LU-11111 lfsck: skip orphan processing" to fix the common cause of crashes due to LFSCK processing open-unlinked files, there is still a potential improvement in orphan processing remaining in patch https://review.whamcloud.com/34174 to limit the scope of the 32959 patch to namespace scanning rather than layout scanning, in case the open-unlinked file is also corrupted.

This patch is for tracking the second patch.