Because we do not have a .testr.conf configuration file the call of
python setup.py testr will fail.
Change-Id: I04a7111fb63a10c5b9631633d54f4b2b3508a6bc
As per the governance resolution https://review.openstack.org/119875,
projects should have a docs environment in their tox.ini testing
interface. Rename the doc environment to docs.
Change-Id: Ib3c26755b780e6910df3e18dffc5db24c30c0324