reproducer for CAMEL-7662
The CamelMQTTExampleTest fails with following error in spite of it succeeds if it just runs with "mvn exec:java -PExample -DskipTests=true"

Caused by: java.lang.AssertionError: Dispatch queue 'mqtt client' was not executing, (currently executing: '<not-dispatched>')
	at org.fusesource.hawtdispatch.internal.SerialDispatchQueue.assertExecuting(SerialDispatchQueue.java:145)
	at org.fusesource.mqtt.client.CallbackConnection.publish(CallbackConnection.java:585)
	at org.fusesource.mqtt.client.CallbackConnection.publish(CallbackConnection.java:581)
	at org.apache.camel.component.mqtt.MQTTEndpoint.publish(MQTTEndpoint.java:160)
	at org.apache.camel.component.mqtt.MQTTProducer.process(MQTTProducer.java:58)
	at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:120)