Changed private: to protected: to fix build issue under OSX
Changed private: to protected: to fix build issue under OSX


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