xfs/096: strip log stripe warnings from mkfs.xfs

xfs/096: strip log stripe warnings from mkfs.xfs

The warnings have been removed when stripe unit/width are too big
for the log stripe unit to be set. Hence add them to the mkfs.xfs
filter and strip them from golden output file so the test succeeds
on both new and old mfks binaries.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>