Add log info for AMQP client
Add log info for AMQP client

If librabbitmq is installed and can be imported correctly, it will
be used as AMQP client to connect RabbitMQ. Mark it in the log file.

Change-Id: I33807df67dd2fffa13c675324c8cc7ae716a210e
Signed-off-by: Kui Shi <691ec1bdbc83cdc4c2e47935b886c1f111c1f1fb@gmail.com>

apporc/oslo.messaging,dims/oslo.messaging,apporc/oslo.messaging,ozamiatin/oslo.messaging,dims/oslo.messaging,dukhlov/oslo.messaging,ozamiatin/oslo.messaging,dukhlov/oslo.messaging