common: handle peer input before gossipd input (for closingd, openingd)

Similar to the previous "handle peer input before gossip input", this
fixes similar potential deadlock for closingd and openingd which use
peer_or_gossip_sync_read.

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

common/read_peer_msg.c

@@ -26,18 +26,18 @@ u8 *peer_or_gossip_sync_read(const tal_t *ctx,
 	select(peer_fd > gossip_fd ? peer_fd + 1 : gossip_fd + 1,
 	       &readfds, NULL, NULL, NULL);
 
-	if (FD_ISSET(gossip_fd, &readfds)) {
-		msg = wire_sync_read(ctx, gossip_fd);
-		if (!msg)
-			status_failed(STATUS_FAIL_GOSSIP_IO,
-				      "Error reading gossip msg: %s",
-				      strerror(errno));
-		*from_gossipd = true;
+	if (FD_ISSET(peer_fd, &readfds)) {
+		msg = sync_crypto_read(ctx, cs, peer_fd);
+		*from_gossipd = false;
 		return msg;
 	}
 
-	msg = sync_crypto_read(ctx, cs, peer_fd);
-	*from_gossipd = false;
+	msg = wire_sync_read(ctx, gossip_fd);
+	if (!msg)
+		status_failed(STATUS_FAIL_GOSSIP_IO,
+			      "Error reading gossip msg: %s",
+			      strerror(errno));
+	*from_gossipd = true;
 	return msg;
 }