connectd: make sure we do IO logging on final_msg output.

This happens when we send a warning or lightningd tells us to send a
final message then close.  Normally io logging is done by the
subdaemon that creates it, but this is a special case.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

connectd/multiplex.c

@@ -577,6 +577,8 @@ static struct io_plan *write_to_peer(struct io_conn *peer_conn,
 		/* OK, send this then close. */
 		msg = peer->final_msg;
 		peer->final_msg = NULL;
+		/* Wasn't logged earlier, so do it now */
+		status_peer_io(LOG_IO_OUT, &peer->id, msg);
 	}
 
 	/* Still nothing to send? */