before owner_sid and group_sid so that well_known_world_sid
means "other" even when owner_sid and/or group_sid are Everyone.
* security.cc (get_attribute_from_acl): Created from code common
to get_nt_attribute() and get_nt_object_attribute(), with same
reordering as in getacl() above.
(get_nt_attribute): Call get_attribute_from_acl().
(get_nt_object_attribute): Ditto.