Fix handling of clutter_init() failures

clutter_init() fails under normal circumstances like
being unable to open a display connection, so it shouldn't
be handled with g_error() producing a core dump.

Clutter consistently produces an error message when
clutter_init() fails, so we don't need to print out any
error message.

https://bugzilla.gnome.org/show_bug.cgi?id=643910

src/run-js-test.c

@@ -78,7 +78,7 @@ main(int argc, char **argv)
   clutter_x11_disable_event_retrieval ();
 
   if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
-    g_error ("failed to initialize Clutter");
+    return 1;
 
   gdk_window_add_filter (NULL, event_filter, NULL);