Enable DeprecationWarning in test environments
Enable DeprecationWarning in test environments

Many deprecations are triggered early (on imports, for example).
To make sure all DeprecationWarning messages are emitted we enable
them via the PYTHONWARNINGS environment variable.

Change-Id: Ia4a90a76dced55f1477010a6b918d8dbb7b82093

openstack/smaug,openstack/smaug