Add get_backdoor_port to consoleauth.

This adds a get_backdoor_port function to the consoleauth
service which enables returning the eventlet_backdoor port
from rpc for the service.

Change-Id: I7da9cbc8111342b5f49f148a8e3389faf5c4f2ab
Fix tests/baremetal/test_driver.py

Unit tests for baremetal/driver.py were not functioning and were
falsely reporting success due to inheriting from the wrong class.
This lead to drift between the tests and the code over time.
I decided it was easier to re-implement tests/baremetal/test_driver.py
instead of trying to fix the drift. This gave me the chance to make
the test class easier to extend. Additional tests will be added
in the future, when I refactor driver.py:spawn().

This patch also has some minor variable name changes for baremetal/driver.py.

blueprint general-bare-metal-provisioning-framework.

Change-Id: I36ba5ed340b722b9a6e8d02d6d57d3c8d53b1eef
Merge "Add get_backdoor_port to consoleauth."
Merge "Fix tests/baremetal/test_driver.py"