Merge pull request #525 from PeelTechnologies/515-fix

Ensuring checkPing carries the callback passed by the client

Author: jpwsutton

org.eclipse.paho.client.mqttv3/src/main/java/org/eclipse/paho/client/mqttv3/MqttAsyncClient.java

@@ -1009,7 +1009,7 @@ public IMqttToken checkPing(Object userContext, IMqttActionListener callback) th
 		// @TRACE 117=>
 		log.fine(CLASS_NAME, methodName, "117");
 
-		token = comms.checkForActivity();
+		token = comms.checkForActivity(callback);
 		// @TRACE 118=<
 		log.fine(CLASS_NAME, methodName, "118");