[bugfix] Initial pylint fixes update

- Initial pylint fixes for OpenStack and RHEVM3 python files
- Minor pylint updates to Fedora and RHEL6 & 7 python files
Update pylint fixes update

- Don't change python3 references to older versions of python.
- Don't change existing functionality
Merge pull request #237 from redhatrises/pylint_fixes_2

[bugfix] Initial pylint fixes update