KVM and XEN Disk Management Parity
KVM and XEN Disk Management Parity

Implements blueprint disk-configuration-parity

This change splits local_gb into root_gb and ephemeral_gb. libvirt
interpreted local_gb as what ephemeral_gb is now, whereas XenAPI
interpreted local_gb as what root_gb is now.

Change-Id: I496600991bac1e990326d4ded1607fee08209d68

openstack/oslo.versionedobjects,citrix-openstack-build/oslo.versionedobjects