OmeroPy: src flake8 (III)

See https://trello.com/c/vnojR45Q/43-flake8-omeropy. This PR modifies the files under `components/tools/OmeroPy/src/omero/install` to let it comply with the PEP-8 style.

To review this PR:

- run flake8 on the files and check it is clean
- check the integration tests are still passing
- check the auto-generated configuration page is still working

/cc @ximenesuk 

--no-rebase