Open Stack

Spec: https://review.openstack.org/#/c/603969/

Summary: The spec describes a bunch of mostly-unrelated-to-each-other
API cleanups, listed below. The spec proposes to do them all in a single
microversion.

Consensus:
- 400 for unknown/invalid params in querystring / request body
  => Do it.
- Remove OS-* prefix from request and response field.
  - Proposed alternative: accept either, return both
  => Don't do it (either way)
- Making server representation always consistent among all APIs
returning the complete server representation.
  => Do it (in the same microversion)
- Return ``servers`` field as an empty list in response of GET
/os-hypervisors when there are no servers (currently it is omitted)
  => Do it (in the same microversion)
- Consistent error codes on quota exceeded
  => Don't do it
- Lump https://review.opendev.org/#/c/648919/ (change flavors.swap
default from '' [string] to 0 [int] in the response) into the same effort?
  => Do it (in the same microversion)

efried
.