Add common_deploy_steps to post_upgrade_steps.
Add common_deploy_steps to post_upgrade_steps.

When refactoring deploy-steps to add a common playbook [0] it seems that
the post_upgrade_steps_playbook block was missed. As a consequence, when
executing the post_upgrade_tasks some of the common Ansible variables
are not available.

[0] - Ib00e8aa9f7d06517290543a8aaf8a2527969bd3c

Change-Id: I04704a14a8b932e21d21348e10014c707a87eeeb
Closes-Bug: #1875579

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates