lightningd/gossip: Fix return from gossip.

We should check that the peer it says it's returning is under its control,
we need to take back the peer fd, and use the correct conversion routine
for the packet it sends us.

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

lightningd/gossip_control.c

@@ -10,6 +10,7 @@
 #include <lightningd/cryptomsg.h>
 #include <lightningd/gossip/gen_gossip_control_wire.h>
 #include <lightningd/gossip/gen_gossip_status_wire.h>
+#include <wire/gen_peer_wire.h>
 
 static void gossip_finished(struct subdaemon *gossip, int status)
 {
@@ -57,11 +58,16 @@ static void peer_nongossip(struct subdaemon *gossip, const u8 *msg, int fd)
 	if (!peer)
 		fatal("Gossip gave bad peerid %"PRIu64, unique_id);
 
-	log_debug(gossip->log, "Peer %s said %s",
-		  type_to_string(msg, struct pubkey, peer->id),
-		  gossip_status_wire_type_name(fromwire_peektype(inner)));
+	if (peer->owner != gossip)
+		fatal("Gossip gave bad peerid %"PRIu64" (owner %s)",
+		      unique_id, peer->owner ? peer->owner->name : "(none)");
+
+	/* It returned the fd. */
+	assert(peer->fd == -1);
+	peer->fd = fd;
+
 	peer_set_condition(peer, "Gossip ended up receipt of %s",
-			 gossip_status_wire_type_name(fromwire_peektype(inner)));
+			   wire_type_name(fromwire_peektype(inner)));
 
 	/* FIXME: create new daemon to handle peer. */
 }