Moved the thread pool executor object from GenericDAO to the DatabaseUtil class where it was actually used: this change simplifies the API and allows to shutdown the pool when it is no more needed.
Removed a series of methods that are no more needed after this refactoring or were not used.

git-svn-id: https://svn.apache.org/repos/asf/ofbiz/trunk@1627092 13f79535-47bb-0310-9956-ffa450edef68