ClutterStageView: Initialize viewport/projection as dirty

Initially the viewport and projection is not calculated and should thus
be marked as dirty.

https://bugzilla.gnome.org/show_bug.cgi?id=768976

clutter/clutter/clutter-stage-view.c

@@ -157,6 +157,11 @@ clutter_stage_view_dispose (GObject *object)
 static void
 clutter_stage_view_init (ClutterStageView *view)
 {
+  ClutterStageViewPrivate *priv =
+    clutter_stage_view_get_instance_private (view);
+
+  priv->dirty_viewport = TRUE;
+  priv->dirty_projection = TRUE;
 }
 
 static void