_cullMaskRight was not being initialized in the constructor which was

resulting in some sporadic problems when running stereo - occoasionally the
right eye view wouldn't appear!

src/osgUtil/SceneView.cpp

@@ -37,7 +37,7 @@ SceneView::SceneView(DisplaySettings* ds)
 
     _cullMask = 0xffffffff;
     _cullMaskLeft = 0xffffffff;
-    _cullMaskLeft = 0xffffffff;
+    _cullMaskRight = 0xffffffff;
 
 }