compositor: stop sending spurious events on mode switch

commit 6ae7bc982f accidentally made weston_output_mode_switch_temporary
send done events when it shouldn't.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

src/compositor.c

@@ -148,6 +148,9 @@ static void weston_mode_switch_finish(struct weston_output *output,
 
 	pixman_region32_fini(&old_output_region);
 
+	if (!mode_changed && !scale_changed)
+		return;
+
 	/* notify clients of the changes */
 	wl_resource_for_each(resource, &output->resource_list) {
 		if (mode_changed) {