Revert previous commit. We still want to call setgroups in the case where

Revert previous commit.  We still want to call setgroups in the case where
there are zero groups to remove any that we might otherwise inherit (as
pointed out by grawity at gmail.com) and since the 2nd argument to
setgroups is always a static global it's always valid to dereference in
this case.  ok deraadt@ djm@