Fix post workarounds
Fix post workarounds

The post tasks stage can run without --version parameter.

To check for the currently installed version we need to
use undercloud_version fact on the undercloud host.

RHOSINFRA-1739

Change-Id: I530292660e1625b91e56b9ce8af3a872fd8aed35

redhat-openstack/infrared,redhat-openstack/infrared,redhat-openstack/infrared