Description of problem:

Platform BZ for https://issues.jboss.org/browse/JBPM-4246

Steps to Reproduce:
1. See https://github.com/droolsjbpm/jbpm/pull/191

Actual results:

EventTypes are inserted when a process instance started and then exist until a process instance completes.

Expected results:

EventTypes are inserted when a process instance arrives at EventNode and then removed after leaving the EventNode.