Fixed bug where the Optimizer::StateVisitor was trying to optimize non existant StateSet's.
Fixed bug where the Optimizer::StateVisitor was trying to optimize
non existant StateSet's.


artoolkit/osg,stmh/osg,koshman86/osg,ntoand/osg,ghub/osg,ghub/osg,omega-hub/osg,XiaoCC/osg,XiaoCC/osg,XiaoCC/osg,ntoand/osg,koshman86/osg,omega-hub/osg,stmh/osg,artoolkit/osg,XiaoCC/osg,koshman86/osg,ghub/osg,stmh/osg,artoolkit/osg,ntoand/osg,stmh/osg,omega-hub/osg,stmh/osg,ntoand/osg,koshman86/osg,artoolkit/osg,XiaoCC/osg,ghub/osg,omega-hub/osg