wallet: don't leak string on update.

We actually don't need tal_fmt() here at all, anyway.

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

wallet/wallet.c

@@ -622,7 +622,7 @@ void wallet_channel_save(struct wallet *w, struct wallet_channel *chan){
 	wallet_channel_config_save(w, &p->our_config);
 
 	/* Now do the real update */
-	stmt = db_prepare(w->db, tal_fmt(w, "UPDATE channels SET"
+	stmt = db_prepare(w->db, "UPDATE channels SET"
 			  "  shachain_remote_id=?,"
 			  "  short_channel_id=?,"
 			  "  state=?,"
@@ -642,7 +642,7 @@ void wallet_channel_save(struct wallet *w, struct wallet_channel *chan){
 			  "  shutdown_keyidx_local=?,"
 			  "  channel_config_local=?,"
 			  "  last_tx=?, last_sig=?"
-					 " WHERE id=?"));
+			  " WHERE id=?");
 	sqlite3_bind_int64(stmt, 1, p->their_shachain.id);
 	if (p->scid)
 		sqlite3_bind_short_channel_id(stmt, 2, p->scid);