Instead of allowing any volume_driver value to be accepted by the
baymodel API. When creating baymodel, the patch can limit the
volume_driver value for the different coe.
Kubernetes <=> volume_driver = "cinder"
Swarm <=> volume_driver = "rexray"
Mesos <=> volume_driver = "rexray"
Co-Authored By: Kai Qiang Wu(Kennan)<wkqwu@cn.ibm.com>
Co-Authored By: Ton Ngo<ton@us.ibm.com>
Partially-Implements: blueprint magnum-integrate-with-cinder
Depends-On: I52c97e2b04ac636ddac611e3677c4ea3972220eb
Change-Id: I25f1cd005a39950c47f31a8b925f664909b79ee3