Comment 3 for bug 1674947

According to http://docs.ansible.com/ansible/playbooks_variables.html the variable "ansible_play_batch" is the replacement for "play_hosts." I found and replaced all entries with the updated variable name.

The master (Pike) branch is using Ansible 2.3, Ocata is using 2.2, and Newton is using 2.1. Maybe we can have this also back-ported to the Ocata branch.