Integrate VMDK driver with oslo.vmware library

The common code between various VMware drivers was moved to the oslo.vmware
library during Icehouse release. The VMDK driver should be updated to use
this library.

Change-Id: I534381608cd6794a5978eb3b41307082cf6a9491
Implements: blueprint vmdk-oslo.vmware
Merge "Integrate VMDK driver with oslo.vmware library"