Updated openstack/openstack
Project: openstack/taskflow  2a0d059700b7c92d81fdb743337b9d14475b78ca

Remove the base postfix for engine abstract base class

Remove the non-standard pattern of calling the engine
base class EngineBase; since it's already obvious that
its a base class by it existing in the base engine
module.

Change-Id: Ia146ec6541ee96aa6a78fa659267d2a69e3b9e97