BugLink: https://bugs.launchpad.net/bugs/2004429
Switch to using a python3 compatible branch for the kernel-testing
scripts used for running autopkgtest. This in turn uses a python3
compatible fork of autotest.
Remove the autopkgtest dependency on python2, replacing it with python3.
Also remove the dependency on bzr as it's unused.
Signed-off-by: Francis Ginther <francis.ginther@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>