LU-11867 osd-ldiskfs: FID in LMA mismatch won't block create

LU-11867 osd-ldiskfs: FID in LMA mismatch won't block create

Sometimes two OST objects may be mapped to the same inode, so the
second object FID mismatch with FID in inode LMA, in this case,
if this inode was not written yet, it's safe to set object inode
to NULL to let it create a new inode.

Another case is if the mapped inode doesn't exist, it's also safe
to not initialize inode and return 0, so that create can succeed.

Add sanity-scrub.sh 4d for this.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: Ic84cdeaca2ea202ab0c01a0075a2f9ee8627f508
Reviewed-on: https://review.whamcloud.com/34052
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>