novaclient provides version negotiation on CLI layer. In case of usage
novaclient as a lib, user can specify api_version with microversion part
and can try communicate with Nova endpoint which doesn't support
microversions. Nova endpoint will not check X-OpenStack-Nova-API-Version
header and will execute request(it can be correct or not). It this case
we should warn user about his mistake and about "incorrect" response.
Change-Id: I7a5ab964b7b2b2a49cc80c22bf67ad5548afb30b