A recent change to the server_roles fixture has made it easier to use, but it will likely conflict with this branch. It should fail on code related to `server_roles`, primarily in the `fixtureconf` mark.

Specifically:
- `default_roles` has gone away and should no longer be imported. Since they're the default, `server_roles` has been modified to be based off of them.
- `server_roles` now add or removes roles, rather than taking a complete set of roles
- To add roles:
  - `@pytest.mark.fixtureconf(server_roles='+automate')` or
  - `@pytest.mark.fixtureconf(server_roles='automate')` (leave the + off, adding roles is implied)
- To remove roles:
  - `@pytest.mark.fixtureconf(server_roles='-automate')

More advanced usage can be found in the fixture docstring:
https://github.com/RedHatQE/cfme_tests/blob/master/fixtures/server_roles.py#L25 or `py.test --fixtures | less` and scroll down to server_roles.