OcclusionQueryNode: reset the test result of the invalid geometry
OcclusionQueryNode: reset the test result of the invalid geometry

There're cases that the occlusion test result has been retrieved
after the query geometry has been changed, it's the result of the
geometry before the change.

openscenegraph/osg,scrawl/osg,openscenegraph/osg,openscenegraph/osg,openscenegraph/osg,scrawl/osg,scrawl/osg,scrawl/osg