Remove unused VMWare VIF driver abstraction

There is only a single VMWare VIF driver impl and that is
entirely a no-op in the plug & unplug methods. The VMWare
driver does call a 'ensure_vlan_bridge' method, which is
essentially a static helper for creating a bridge device.

Remove the VMWareVlanBridgeDriver class entirely and simply
have a single static method instead

Change-Id: I7d0873798e0e7261e17e8894237fd4339be7c3cd
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Merge "Remove unused VMWare VIF driver abstraction"