gtk-clutter-embed: don't use queue redraw on gtk+'s draw()

Calling clutter_actor_queue_redraw() triggers an asynchronous redraw
cycle, which triggers the callback from gtk-clutter-embed on the
'queue-redraw' signal, thus triggering another GTK+ paint cycle.

This ends up in a infinite draw loop.

This patch uses the clutter_stage_ensure_redraw() methods, which
prevents the 'queue-redraw' signal emission (this is exactly what we
want).

https://bugzilla.gnome.org/show_bug.cgi?id=734906