Not probing for microversion correctly

[Ian Kumlien]

The current version doesn't probe for microversion - version discovery has been documented for a long time:
https://docs.openstack.org/api-guide/compute/microversions.html

But we still have to do special workarounds for commands that require higher microversions...

It seems like you actually do query microversion for the shell, but not for the client.

uncommenting this in novaclient/client.py:
        # TODO(andreykurilin): uncomment this line, when we will be able to
        # check only nova-related calls
        #api_versions.check_headers(resp, self.api_version)
---

Shows that the nova server instance doesn't actually present the microversion, thus there would have to be a proper query, and since it's slow... it should be done early in the client and saved as environment variables and thus reused as a cache...