ReNo [1] is the release management tool in OpenStack.
This patch adds the basic structure to start using it.
* Update .gitignore
* Add releasenotes/ dir and basic files
* Add python files: setup.cfg, setup.py, test-requirements.txt and
tox.ini.
[1] http://docs.openstack.org/developer/reno
Change-Id: I3fb6945c200db9fa53dab15ccee3e9e7f94ec2ba