Remove Virtual Storage Array (VSA) code
Remove Virtual Storage Array (VSA) code

* Remove core vsa code (api, manager, drivers)
* Remove nova-vsa executable
* Remove OpenStack Compute API v2 vsa extension
* Remove vsa scheduler
* Remove vsa db api methods
* Remove Zadara volume driver
* Do not migrate out any existing data
* Fixes bug 954490

Change-Id: Idab3d60796d5edbc23ef9f0887fcc1af558c6215

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