xfs/108: allow slightly higher block usage

xfs/108: allow slightly higher block usage

With pmem and fsdax enabled, I occasionally see this test fail on XFS:

   Mode: (0600/-rw-------)         Uid: (1)  Gid: (2)
 Disk quotas for User #1 (1)
 Filesystem Blocks Quota Limit Warn/Time Mounted on
-SCRATCH_DEV 48M 0 0 00 [------] SCRATCH_MNT
+SCRATCH_DEV 48.0M 0 0 00 [------] SCRATCH_MNT
 Disk quotas for User #1 (1)
 Filesystem Files Quota Limit Warn/Time Mounted on
 SCRATCH_DEV 3 0 0 00 [------] SCRATCH_MNT

The cause of this failure is fragmentation in the file mappings that
results in a block mapping structure that no longer fits in the inode.
Hence the block usage is 49160K instead of the 49152K that was written.
Use some fugly sed duct tape to make this test accomodate this
possiblity.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>