As a part of the python 3 community goal, this converts the functional
tests to run with python3 by default, and in Zuul.
As discussed at the Stein PTG in Denver, unit and functional tests will
still run on both versions, so this adds a python2 job for functional
This patch also suppress logging levels from some external libraries
to avoid issues with subunit.parser and python 3. For details see bug
reported for Cinder .
Co-Authored-By: Slawek Kaplonski <email@example.com>