Remove duplicate error on error path.

There's an extra error() call on the listen error path, it looks like
its removal was missed during an upstream sync.

channels.c

@@ -3448,7 +3448,6 @@ channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type,
 		}
 		/* Start listening for connections on the socket. */
 		if (listen(sock, SSH_LISTEN_BACKLOG) == -1) {
-			error("listen: %.100s", strerror(errno));
 			error("listen [%s]:%s: %.100s", ntop, strport,
 			    strerror(errno));
 			close(sock);