It would be *really* cool and useful and stuff to be able to run
the Ansible playbooks against more than just devstack. This change
allows that. Now you can send the -c option to the tox command line:
tox -e ansible -- -c coolcloud
Or, specific tests:
tox -e ansible -- -c coolcloud auth network
Going against devstack is still:
tox -e ansible
tox -e ansible auth network
Change-Id: I666a09aee3d283865c3813d67edfb75123057c22