Report Error from RabbitMQ Plugin
Report Error from RabbitMQ Plugin

In monasca agent rabbitmq plugin, if it receives an HTTP error, it
only logs it instead of report the error back to the caller.

Change-Id: Ibbd4e4917eb42f46097dbb738bf1b50317578cdf

sapcc/monasca-agent,sapcc/monasca-agent,sapcc/monasca-agent