KYLIN-946 ,fix selectedNode NULL exception
KYLIN-946 ,fix selectedNode NULL exception

lemire/incubator-kylin,haoch/kylin,haoch/kylin,murkrishn/incubator-kylin,murkrishn/incubator-kylin,murkrishn/incubator-kylin,murkrishn/incubator-kylin,haoch/kylin,lemire/incubator-kylin,lemire/incubator-kylin,haoch/kylin,haoch/kylin,haoch/kylin,lemire/incubator-kylin