Add tests for Nova microversion v2.2

In Nova microversion v2.2, keypair APIs have been changed.
It allow to specify the keypair type in request and same will
be return in response. Along with there are status code changes
also.
Ref-
http://docs.openstack.org/developer/nova/api_microversion_history.html#id2

This commit add Tempest tests for Nova version v2.2 and version
the required schema also.

Partially implements blueprint api-microversions-testing-support

Change-Id: I7917865ab5abb703049160c695550e15441c55e0
6 files changed