Pin importlib-resources to fix virtualenv and tox

Work around this bug [0] via downgrade of importlib-resources.

Note that we skip the base-test phase because this task is set to not
fail. If we have problems we should be able to debug live.

[0] https://gitlab.com/python-devs/importlib_resources/issues/83

Change-Id: Ia8bbcbc734bc7fe3d7e553e51d67a4ed0ae1404e

playbooks/base/pre.yaml

@@ -46,3 +46,19 @@
     - mirror-info
     - role: configure-mirrors
       set_apt_mirrors_trusted: True
+  post_tasks:
+    - name: Pin importlib-resources to 1.0.2 to fix Virtualenv and Tox
+      become: yes
+      shell: |
+        if type -p pip3 ; then
+          # Tox and virtualenv will be python3 installed on platforms with pip3
+          pip3 install --upgrade importlib-resources==1.0.2
+        else
+          # Centos 7 shouldnt have python3 by default and need a pip2 install
+          pip install --upgrade importlib-resources==1.0.2
+        fi
+      args:
+        executable: /bin/bash
+      # Do our best but if we fail don't cause job to fail as it may run
+      # happily without virtualenv or tox.
+      failed_when: false