commit 12337901 upstream.

Note nobody's ever noticed because the typical client probably never
requests FILES_AVAIL without also requesting something else on the list.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>