Inaccurate reporting of number of message delivered over websockets

[uvzubovs]

I have producer publishing over straight MQTT and consumer subscribed over websockets.

Consumer receives messages, but $SYS/broker/broker_publish_messages_sent (I think this is the number of messages delivered by the broker to the consumer) remains at zero, whereas $SYS/broker/broker_publish_messages_received reflects the number of messages published. $SYS/broker/broker_publish_bytes_sent seems to increment properly, though.

Note that broker_publish_messages_sent increments in tandem with broker_publish_messages_received if consumer is subscribed over straight MQTT.

[PierreF]

Some counter were not updated when a message is sent over Websockets. Those counter are:

• $SYS/broker/messages/sent
• $SYS/broker/publish/messages/sent
• $SYS/broker/bytes/sent

A fix is committed on branch fixes.