Fix amphora image build jobs

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

playbooks/image-build/run.yaml

@@ -7,7 +7,7 @@
         update_cache: yes
       register: install_packages
       become: yes
-      until: install_packages|success
+      until: install_packages is success
       retries: 5
       delay: 2
       with_items:
@@ -21,13 +21,16 @@
         - bc
         - rpm
         - yum-utils
+        - python3-venv
+        - python3-setuptools
     - name: Install required pip packages
       pip:
         name: "{{  item }}"
         state: "latest"
         virtualenv: /var/tmp/venv
+        virtualenv_command: python3 -m venv
       register: install_packages
-      until: install_packages|success
+      until: install_packages is success
       retries: 5
       delay: 2
       become: yes