Make utility install playbook idempotent
Make utility install playbook idempotent

To ensure idempotence we do the following:

1. Ensure that the symlinks are only changed if
   they do not yet exist.
2. Switch the openstack client bash completion to
   be a handler which is executed whenever the
   venv changes or the symlinks change.

Change-Id: I6e3ae377c37fb8b72b5ff913154f7763d1691b25

stackforge/os-ansible-deployment,openstack/openstack-ansible,openstack/openstack-ansible,stackforge/os-ansible-deployment