This is a mechanically generated patch to ensure unit testing is in place
for all of the Tested Runtimes for Train.
See the Train python3-updates goal document for details:
https://governance.openstack.org/tc/goals/train/python3-updates.html
Change-Id: I7ee18992a3f769a029157e09e5b7911660c7a910
We want to default to running all tox environments under python 3, so
set the basepython value in each environment.
We do not want to specify a minor version number, because we do not
want to have to update the file every time we upgrade python.
We do not want to set the override once in testenv, because that
breaks the more specific versions used in default environments like
py35 and py36.
Change-Id: I816afc3b54935c4e000ed9a2bd09ecc4b283b0f2
Ghanshyam Mann