fstests: filter mount error message for EUCLEAN and ESTALE

util-linux commit ea848180dd34 ("libmount: add
mnt_context_get_excode()") since v2.30 changed the error message on
EUCLEAN and ESTALE again (and maybe other errno too):

 - mount: <device> on <mountpoint> failed: Structure needs cleaning
 + mount: <mountpoint>: mount(2) system call failed: Structure needs cleaning.

and it causes xfs/005, overlay/037 to fail (and probably xfs/333 too,
but it's always _notrun for now).

And what's more, the mentioned tests would also fail when testing
with util-linux prior to v2.21, no one complained just because the
tests are usually _notrun on such old distributions that ship
util-linux < v2.21.

So let's filter out the changing parts and keep the error message
simple.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

tests/xfs/005

@@ -40,11 +40,6 @@ _cleanup()
     rm -f $tmp.*
 }
 
-filter_mount()
-{
-	sed -e "s/mount .* failed: //"
-}
-
 # get standard environment, filters and checks
 . ./common/rc
 . ./common/filter
@@ -64,7 +59,7 @@ _scratch_mkfs_xfs -m crc=1 >> $seqres.full 2>&1 || _fail "mkfs failed"
 $XFS_IO_PROG -c "pwrite 224 4" -c fsync $SCRATCH_DEV | _filter_xfs_io
 
 # should FAIL, the crc is bad; golden output contains mount failure
-_scratch_mount 2>&1 | filter_mount
+_scratch_mount 2>&1 | _filter_error_mount
 
 # success, all done
 status=0