This reverts commit 8e104b3c54.
https://review.openstack.org/#/c/559926/ introduced requiring CloudName.
This broke the documented deployment process. I also don't see how
CloudName can be required, but CloudDomain can not.
I don't see a technical reason why we can't keep the default as
localdomain. If necessary, we can instead add a parameter
validation instead of requiring the parameter.