Style changes: Adapt to newer pyflakes.

test_refactor: Remove superfluous newline.
pydocutils: Rename variable in list comprehension that was shadowing
another variable name.
virtualenv-workon/deactivate: Do not ask the user if no Elpy is running.

Elpy used to ask the user about restarting the backend even when there
was no backend running. This change will make it stop doing so. Also,
it will not ask if `virtualenv-workon-starts-python` is nil, because
that's how virtualenv controls that behavior (somewhat; virtualenv
always kills the process, I think).