added comment about setting mqtt broker

Author: janvda

node-red-test/appmetrics.properties

@@ -1,5 +1,7 @@
 # MQTT connection properties
 com.ibm.diagnostics.healthcenter.mqtt=on
+
+# JVA 2018-11-26: changed localhost into mqtt
 com.ibm.diagnostics.healthcenter.mqtt.broker.host=mqtt
 com.ibm.diagnostics.healthcenter.mqtt.broker.port=1883
 #com.ibm.diagnostics.healthcenter.mqtt.topic.namespace=myApplication/namespace