Snapshot - MQTT logging

I’ve just updated from OH V2.1 to the latest Snapshot build, and would like to tame the MQTT logging, I did this in OH V2.1 by adding

log4j.logger.org.openhab.io.transport.mqtt.internal.MqttBrokerConnection = ERROR

to /var/lib/etc/org.ops4j.pax.logging.cfg. However in the later Snapshot it doesn’t work, and neither does

log4j2.logger.org.openhab.io.transport.mqtt.internal.MqttBrokerConnection = ERROR

Can someone please tell me what the correct syntax is, as I still get this in the logs after every message when I reboot one of my Pi’s

2017-12-12 09:03:21.105 [WARN ] [t.mqtt.internal.MqttBrokerConnection] - Broker connection not started. Cannot publish message to topic 'Upstairs/Status/HWCPower'