xfs: don't return _QUERY_ABORT from xfs_rmap_has_other_keys

The xfs_rmap_has_other_keys helper aborts the iteration as soon as it
has an answer.  Don't let this abort leak out to callers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>