fs/cifs: fix regression in cifs_create_mf_symlink()

commit d81b8a40
("CIFS: Cleanup cifs open codepath")
changed disposition to FILE_OPEN.

Signed-off-by: Björn Baumbach <bb@sernet.de>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Cc: <stable@vger.kernel.org> # v3.14+
Cc: Pavel Shilovsky <piastry@etersoft.ru>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>