compositor-wayland: fix memory leak of display_name

Signed-off-by: Benoit Gschwind <gschwind@gnu-log.net>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

src/compositor-wayland.c

@@ -2440,9 +2440,11 @@ backend_init(struct weston_compositor *compositor, int *argc, char *argv[],
 				          MODIFIER_CTRL | MODIFIER_ALT,
 				          fullscreen_binding, b);
 
+	free(new_config.display_name);
 	return 0;
 
 err_outputs:
 	wayland_backend_destroy(b);
+	free(new_config.display_name);
 	return -1;
 }