Ansible launcher: install libselinux-python if necessary
Ansible launcher: install libselinux-python if necessary

This is temporary until we rebuild images with the zuul-worker
dib element.

Change-Id: Ic1c2a60ab87ad96a0b2b050c6f568d3946b30466

wikimedia/integration-zuul,gooddata/zuul,gooddata/zuul,gooddata/zuul,gooddata/zuul,wikimedia/integration-zuul,gooddata/zuul,wikimedia/integration-zuul,wikimedia/integration-zuul