Make nat behave the way it used to by copying back the random source port correctly. Also remove some extra cruft in pf_get_sport related to the "static-port" behaviour.
Make nat behave the way it used to by copying back the random source port
correctly. Also remove some extra cruft in pf_get_sport related to the
"static-port" behaviour.

bug report from mpech@ and form@
testing cedric@
"looks sane to me" henning@
ok dhartmei@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars