The new PIP resolver wreaks havoc for this repository.
Long term we should split unit test requirements into a separate
file and whip unit tests into shape wrt. mocking out everything as
opposed to relying on having random modules installed in the test
environment.
Add Python 3.8 env in Travis CI test matrix.
At present the pinning of flake8 disallows running of lint on
Python 3.8 systems.
Update flake8 ignore-list to ignore W504 instead of W503, the PEP
guidance is that either is ok, but there must be local consistency.
There are more occurences of binary operator before line-break
than after in this repository, and we have also chosen to ignore
W504 in most of our other repositories.
* Addition of the (incomplete) openstack-dashboard test.
* Modification of other charm policyd override tests to support
multi-file policy overrides resource ZIP.
