Make cppcheck happy and code clearer.

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

hsmd/hsm.c

@@ -610,7 +610,7 @@ static void sign_funding_tx(struct daemon_conn *master, const u8 *msg)
 	struct bitcoin_tx *tx;
 	u16 outnum;
 	size_t i;
-	struct pubkey changekey;
+	const struct pubkey *changekey;
 	u8 **scriptSigs;
 
 	/* FIXME: Check fee is "reasonable" */
@@ -620,13 +620,16 @@ static void sign_funding_tx(struct daemon_conn *master, const u8 *msg)
 				       &remote_pubkey, &utxomap))
 		master_badmsg(WIRE_HSM_SIGN_FUNDING, msg);
 
-	if (change_out)
+	if (change_out) {
-		bitcoin_pubkey(&changekey, change_keyindex);
+		changekey = tal(tmpctx, struct pubkey);
+		bitcoin_pubkey(changekey, change_keyindex);
+	} else
+		changekey = NULL;
 
 	tx = funding_tx(tmpctx, &outnum,
 			cast_const2(const struct utxo **, utxomap),
 			satoshi_out, &local_pubkey, &remote_pubkey,
-			change_out, &changekey,
+			change_out, changekey,
 			NULL);
 
 	scriptSigs = tal_arr(tmpctx, u8*, tal_count(utxomap));

openingd/opening.c

@@ -214,7 +214,8 @@ static u8 *funder_channel(struct state *state,
 	u8 *msg;
 	struct bitcoin_tx *tx;
 	struct basepoints theirs;
-	struct pubkey their_funding_pubkey, changekey;
+	struct pubkey their_funding_pubkey;
+	const struct pubkey *changekey;
 	secp256k1_ecdsa_signature sig;
 	u32 minimum_depth;
 	const u8 *wscript;
@@ -322,17 +323,19 @@ static u8 *funder_channel(struct state *state,
 
 	/* Now, ask create funding transaction to pay those two addresses. */
 	if (change_satoshis) {
-		if (!bip32_pubkey(bip32_base, &changekey, change_keyindex))
+		changekey = tal(tmpctx, struct pubkey);
+		if (!bip32_pubkey(bip32_base, changekey, change_keyindex))
 			status_failed(STATUS_FAIL_MASTER_IO,
 				      "Bad change key %u", change_keyindex);
-	}
+	} else
+		changekey = NULL;
 
 	funding = funding_tx(state, &state->funding_txout,
 			     cast_const2(const struct utxo **, utxos),
 			     state->funding_satoshis,
 			     our_funding_pubkey,
 			     &their_funding_pubkey,
-			     change_satoshis, &changekey,
+			     change_satoshis, changekey,
 			     bip32_base);
 	bitcoin_txid(funding, &state->funding_txid);