Our periodic amphora image build jobs started failing around mid June
with:
"The conditional check 'install_packages|success' failed. The error was:
template error while templating string: no filter named 'success'.
String: {% if install_packages|success %} True {% else %} False {% endif
%}"
Filters have changed in Ansible 2.9 after a deprecation period.
Additionally, install python3-venv and set virtualenv_command (defaults
to Python 2 "virtualenv") as it seems to be required now too.
Change-Id: I3efa89992cc4a8e2645803dd867d7d2f6e39b966
9df5f75d49