libratbox: use rb_listen(), not listen().

Signed-off-by: Elly Fong-Jones <elly@leptoquark.net>
(cherry picked from commit 2682bc3)

libratbox/src/gnutls.c

@@ -352,7 +352,7 @@ rb_ssl_listen(rb_fde_t *F, int backlog, int defer_accept)
 {
 	int result;
 
-	result = listen(F->fd, backlog, defer_accept);
+	result = rb_listen(F->fd, backlog, defer_accept);
 	F->type = RB_FD_SOCKET | RB_FD_LISTEN | RB_FD_SSL;
 
 	return result;