This, for example, allows you to run libvirt with non-default
socket path.
Change-Id: Ia01f39f425cccc6acebd31f77b46b1948e24d215
Story: 2004344
Task: 27935
Create a role to configure a host for Virtual BMC, and another to add
domains to it.
Also add some checking to make the roles more robust.
Conflicts:
ansible/deploy.yml
ansible/libvirt_create_vms.yml
ansible/roles/virtualbmc/tasks/main.yml