* Add new Fedora docker images with Python 3.
* Use consistent env var for lookup test.
* Fix testing of virtualenv with Python 3.
* Fix docker_secret tests on Fedora 26.
* Add Python 3 support to Fedora postgresql test.
* Add Python 3 support to Fedora mysql tests.
* Fix uri test server for Python 3 on Fedora.
* Fix iso_extract test for Python 3 on Fedora.
* Add Python 3 support for Fedora to openssl tests.
* Fix dnf group test for Python 3 on Fedora.
* Use force with user deletion in become test.
* Reimplement iso_extract using 7zip (not requiring root)
So one of the drawbacks of the original implementation is that it required root for mounting/unmount the ISO image.
This is now no longer needed as we use 7zip for extracting files from the ISO.
* Fall back to using mount/umount if 7zip not found
As discussed with others.
Also improved integration tests.
