Havana will include a new rev of the compute API. There are a lot of blueprints and a ton of patches that make up this effort. The top level blueprint is here: https://blueprints.launchpad.net/nova/+spec/nova-v3-api
This isn't going to be done for Havana. The API will be present but unfinished and experimental, so this needs to be bumped to RHOS 5.0.
*** Bug 894823 has been marked as a duplicate of this bug. ***
Updating based on BP milesone.