using .host instead of .hostname+.port

The `eventbus` path will not work. When the AeroGear mqttws notifier adapter was created, the eclipse paho [MQTT JavaScript client](https://github.com/tolis-e/aerogear-js-integration/blob/a5a69f8b9dfbc0ff666710108b632ab07eb94dd3/tests/notifier/mqttws31.js#L1446) was only supporting host, port, client id. So the connect URL should be `window.location.protocol + '//' + window.location.host`. However I have just noticed that the API of the [eclipse paho JavaScript client](http://git.eclipse.org/c/paho/org.eclipse.paho.mqtt.javascript.git/tree/src/mqttws31.js) has been changed since then and we should update our adapter as well. The new client supports the path. I will file a JIRA and take it on me.