Messaging driver is extended to read profiling events
from RabbitMQ and generate report. This simplifies
usage of profiling in DevStack since Ceilometer is not
needed anymore.
The typical workflow is following:
1. User issues a command with profiling enabled:
openstack --os-profile SECRET KEY <command>
2. User retrieves the trace:
osprofiler trace show --connection messaging://
--transport-url rabbit://<rabbituser>:<rabbitpassword>@<devstack>:5672/
--json <trace-id>
Change-Id: I950896d6d9156f09e378bdfcf272aef5da4ece74