Since 4301505d977449d core smbd code passes O_NOFOLLOW together with
[O_RDONLY|O_RDWR] as flags. This breaks activating vfs_preopen, we
need to look at *just* the access mode.
Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Michael Adam <obnox@samba.org>