Fix getDeviceInfoForMqtt crash. https://github.com/Koenkk/zigbee2mqtt/issues/632

lib/controller.js

@@ -27,6 +27,7 @@ class Controller {
         this.onMQTTConnected = this.onMQTTConnected.bind(this);
         this.onZigbeeMessage = this.onZigbeeMessage.bind(this);
         this.onMQTTMessage = this.onMQTTMessage.bind(this);
+        this.publishDeviceState = this.publishDeviceState.bind(this);
 
         // Initialize extensions.
         this.extensions = [