Newer tox on focal is not happy when inhieriting dependencies. First in py27 testenv, it does not pickup the 'testenv' deps which includes test-depedndences and dependencies files. Fix this by explicitly referencing these deps fir testenv:py27. Second, in testenv:trusty-p27, which recreates specific package versions to model the trusty build environment we cannot pull in the default testenv deps, as this breaks with different versions of mock and other settings. Instead, just bring in the setuptools dep to ensure we can keep running on py27 for now.