Comment 13 for bug 1541691

I think that https://review.openstack.org/#/c/281143/ broke the openstackclient and novaclient aggregate create CLI. Both allowed made the availability zone optional which results in null being passed to the API.

ubuntu@openstackclient:/opt/stack/python-openstackclient$ openstack aggregate create foo
expected string or buffer (HTTP 400) (Request-ID: req-41d146cf-8ce4-4cce-8371-ffe6e03a3c73)
ubuntu@openstackclient:/opt/stack/python-openstackclient$ nova aggregate-create foo
ERROR (BadRequest): expected string or buffer (HTTP 400) (Request-ID: req-57bdcf61-d7d4-4242-98f6-88204ac3869b)