state: fix BITCOIN_HTLC_TOTHEM_SPENT idata.

We use both union fields idata->btc and idata->htlc, which is clearly
wrong.  Have peer_tx_revealed_r_value return the HTLC it's talking
about.

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

state.c

@@ -757,10 +757,11 @@ enum command_status state(const tal_t *ctx,
 				return next_state(peer, cstatus,
 						  BITS_TO_STATE(bits));
 			} else if (input_is(input, BITCOIN_HTLC_TOTHEM_SPENT)) {
+				const struct htlc *htlc;
 				/* They revealed R value. */
-				peer_tx_revealed_r_value(peer, idata->btc);
+				htlc = peer_tx_revealed_r_value(peer, idata->btc);
 				/* We don't care any more. */
-				peer_unwatch_htlc_output(peer, idata->htlc,
+				peer_unwatch_htlc_output(peer, htlc,
 							 INPUT_NO_MORE_HTLCS);
 				return unchanged_state(cstatus);
 			} else if (input_is(input, BITCOIN_HTLC_TOTHEM_TIMEOUT)){

state.h

@@ -94,8 +94,8 @@ void peer_htlc_done(struct peer *peer);
 void peer_htlc_aborted(struct peer *peer);
 
 /* An on-chain transaction revealed an R value. */
-void peer_tx_revealed_r_value(struct peer *peer,
+const struct htlc *peer_tx_revealed_r_value(struct peer *peer,
-			      const struct bitcoin_event *btc);
+					    const struct bitcoin_event *btc);
 
 /* Create various kinds of packets, allocated off @ctx */
 Pkt *pkt_open(const tal_t *ctx, const struct peer *peer,

test/test_state_coverage.c

@@ -1465,11 +1465,12 @@ void peer_htlc_declined(struct peer *peer, const Pkt *pkt)
 	peer->htlc_declined = true;
 }
 	       
-void peer_tx_revealed_r_value(struct peer *peer,
+const struct htlc *peer_tx_revealed_r_value(struct peer *peer,
-			      const struct bitcoin_event *btc)
+					    const struct bitcoin_event *btc)
 {
 	const struct htlc *htlc = (struct htlc *)btc;
 	add_rval(peer, htlc->id);
+	return htlc;
 }	
 
 static const char *check_changes(const struct peer *old, struct peer *new,