Fixed unused parameter warning.
Fixed unused parameter warning.

tomasthoresen/osg,marchelbling/osg,openscenegraph/osg,jtorresfabra/osg,artoolkit/osg,openscenegraph/osg,openscenegraph/osg,jtorresfabra/osg,artoolkit/osg,jtorresfabra/osg,tomasthoresen/osg,artoolkit/osg,marchelbling/osg,openscenegraph/osg,scrawl/osg,marchelbling/osg,artoolkit/osg,tomasthoresen/osg,scrawl/osg,scrawl/osg,tomasthoresen/osg,marchelbling/osg,scrawl/osg,jtorresfabra/osg