Remove UNIX domain socket raw socket support. This feature is documented

as being undocumented in Stevens, and was broken in 1997 during network
stack infrastructure work.  It is the one remaining (and incorrect)
direct protocol reference to raw_usrreq.pru_attach; this is incorrect
because the raw socket code assumes that raw_uattach is called only after
the protocol has allocated a PCB.

MFC after:	3 months

sys/kern/uipc_proto.c

@@ -61,11 +61,6 @@ static struct protosw localsw[] = {
 	.pr_flags =		PR_ATOMIC|PR_ADDR|PR_RIGHTS,
 	.pr_usrreqs =		&uipc_usrreqs
 },
-{
-	.pr_ctlinput =		raw_ctlinput,
-	.pr_init =		raw_init,
-	.pr_usrreqs =		&raw_usrreqs
-}
 };
 
 struct domain localdomain = {