Fix show-stopper for 3.2. Smbd depends on group SID

Fix show-stopper for 3.2. Smbd depends on group SID
position zero being the primary group sid. Authenicating
via winbindd call returned a non-sorted sid list. This
fixes is for both a winbindd call and a pac list from
an info3 struct. Without this we mess up the
primary group associated with created files. Found by
Herb.
Jeremy.
(This used to be commit cb925dec85cfc4cfc194c3ff76dbeba2bd2178d7)