Agreed.

Open a bug with Zentyal. They broke the packages from Ubuntu and should
fix it themselves. They have to backport newer version of python-apt.
The one from yakkety (1.1.0~beta5) should be good enough to fix the
problem.

In the bug report note that the ovirt-guest-agent from Ubuntu repository
cannot be installed. It is not only related to the package from the
private repo.

Ok, Thank you!