Fixed wrong-buffer bug that resulted in incorrected IP addresses in connection labels.
Added a trace to announce any sent packets on the netmap interface.
Neuter syncache responses differently for passive entries so that the
syncache is always completely silent on the wire and the usual aging
mechanism is used for such entries.
Silence tcp_respond() for passive connections.  There are places where
tcp_respond() might be invoked when doing a passive + promiscuous
listen because of arbitrary packets from the wire matching the
promiscuous inpcb, then later being rejected by the state machine
logic.
Fixed capture of SYN|ACK during passive reconstruction with a fully
promiscuous listen.  Silenced tcp_dropwithreset() for passive
connections as there are places where it may be invoked when doing a
fully promicsuous passive listen.