Also clean up pre-existing pep8 violations in the
files/* dir which was previously not covered by lint testing.

Also clean-up mocking issues around apt-pkg replacements in the
unit tests.

Also fix py35 issue with enabled_manager_modules() function in the
charmhelpers library (see
https://github.com/juju/charm-helpers/pull/387).

Also fix the functional tests bundles so they actually test the
version of OpenStack that the bundle indicates.

Change-Id: I2c8d84fadc11311c622dd308c4694496872dc157