Zero the un-used portions of the struct sockaddr data before sending

it back to userspace, so it does not break bind(2) on raw sockets in jails.

Currently some processes, like traceroute(8) construct a routing request
to determine its source address based on the destination. This sockaddr
data is fed directly to bind(2). When bind calls ifa_ifwithaddr(9) to
make sure the address exists on the interface, the comparison will
fail causing bind(2) to return EADDRNOTAVAIL if the data wasnt zero'ed
before initialization.

Approved by:	bmilekic (mentor)

sys/net/rtsock.c

@@ -404,6 +404,7 @@ route_output(struct mbuf *m, struct socket *so)
 					info.rti_info[RTAX_IFP] =
 					    ifaddr_byindex(ifp->if_index)->ifa_addr;
 					if (jailed(so->so_cred)) {
+						memset(&jail, 0, sizeof(jail));
 						jail.sin_family = PF_INET;
 						jail.sin_len = sizeof(jail);
 						jail.sin_addr.s_addr =