Finish migration to new engine facade in test_db_base_plugin_v2
Finish migration to new engine facade in test_db_base_plugin_v2

Partially-Implements blueprint: enginefacade-switch

Change-Id: I1b95d53f79c2c2b56a119c20017c3bf7fbc8550d

openstack/neutron,mahak/neutron,mahak/neutron,openstack/neutron,openstack/neutron,mahak/neutron