onchain: Load HTLC stubs upon starting onchaind

This wires in the loading of `struct htlc_stub`s on-demand when
starting `onchaind` so that we don't need to keep them in memory.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/peer_control.c

@@ -1400,6 +1400,7 @@ static enum watch_result funding_spent(struct peer *peer,
 	struct sha256_double our_last_txid;
 	s64 keyindex;
 	struct pubkey ourkey;
+	struct htlc_stub *stubs;
 
 	peer_fail_permanent_str(peer, "Funding transaction spent");
 
@@ -1419,6 +1420,12 @@ static enum watch_result funding_spent(struct peer *peer,
 		return KEEP_WATCHING;
 	}
 
+	stubs = wallet_htlc_stubs(peer, peer->ld->wallet, peer->channel);
+	if (!stubs) {
+		log_broken(peer->log, "Could not load htlc_stubs");
+		return KEEP_WATCHING;
+	}
+
 	/* We re-use this key to send other outputs to. */
 	if (peer->local_shutdown_idx >= 0)
 		keyindex = peer->local_shutdown_idx;
@@ -1469,14 +1476,14 @@ static enum watch_result funding_spent(struct peer *peer,
 				  /* FIXME: config for 'reasonable depth' */
 				  3,
 				  peer->last_htlc_sigs,
-				  tal_count(peer->htlcs));
+				  tal_count(stubs));
 	subd_send_msg(peer->owner, take(msg));
 
 	/* FIXME: Don't queue all at once, use an empty cb... */
-	for (size_t i = 0; i < tal_count(peer->htlcs); i++) {
+	for (size_t i = 0; i < tal_count(stubs); i++) {
 		bool tell_immediate;
 		bool tell = tell_if_missing(peer, i, &tell_immediate);
-		msg = towire_onchain_htlc(peer, peer->htlcs+i,
+		msg = towire_onchain_htlc(peer, &stubs[i],
 					  tell, tell_immediate);
 		subd_send_msg(peer->owner, take(msg));
 	}