[tempest] Do not use include_role with delegate_to
[tempest] Do not use include_role with delegate_to

When using Ansible 2.8 the following error will occurr:

ERROR   <class 'ansible.errors.AnsibleParserError'>: 'delegate_to'
is not a valid attribute for a IncludeRole

To resolve this we move the task into its own play in the same
playbook. This should have the same effect as the previous
implementation.

Change-Id: I9b4ae15a6921f01504fb796b894d09db9c022e55

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