xfs/070: filter the bad sb magic number error

xfs/070: filter the bad sb magic number error

Lastest XFS kernel makes the superblock bad magic number error
message more meaningful, and that's being picked up by xfsprogs in
very short order. And, of course, the error is output by xfs_repair,
too, and it's been captured in the golden output of a test. Fix it
by filtering the output back down to the old message.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>