Comment 4 for bug 1867004

- The workdir role is included by external_deploy_steps_tasks only [1]
- The external_deploy_steps_tasks are run against the undercloud node only [2]

So, things I should have asked during the code review:
- Do we want to get running hiera commands on the undercloud?
- Why do we need to this when we already have vars set based on THT, e.g. ceph_pools.glance_pool.enabled?

[1]
(control-plane) [stack@undercloud config-download]$ grep -R work_dir *
external_deploy_steps_tasks.yaml: name: tripleo_ceph_work_dir
external_deploy_steps_tasks.yaml: name: tripleo_ceph_work_dir
(control-plane) [stack@undercloud config-download]$

[2] https://docs.openstack.org/project-deploy-guide/tripleo-docs/latest/deployment/ansible_config_download.html#playbooks