Enable DeprecationWarning in test environments
Enable DeprecationWarning in test environments

Many deprecations are triggered early (on imports, for example)
before the warnings are enabled by the WarningsFixture in the
base test class.

To make sure all DeprecationWarning messages are emitted we enable
them via the PYTHONWARNINGS environment variable.

Change-Id: Ibad285e0a4a1b1e1078aa396bce3a6604fcd5734

celebdor/kuryr,openstack/kuryr,openstack/kuryr,celebdor/kuryr