Removed defaults for login_username and auth_url.

* The login_username defaulting to admin is poor practice.  Users should
  not have admin creds to begin with, and if they do have admin creds, the
  admin role should be applied to their personal login.
* The auth_url defaulting to localhost is not very useful.  Ansible is
  highly unlikely to be running on the machine running the keystone endpoint,
  so this is will be overridden 99% of the time.
* Removed more trailing whitespace terds