remove provider class name in persistence.xml

Hi our persistence.xml file we are (unnecessarily) specifying the class name of the Persistence provider.

• UPS uses simple JPA bits, should work with all JPA impementations, hence a hard coded ref. to Hibernate is odd
• Hibernate 4.3. changed the class name to "org.hibernate.jpa.HibernatePersistenceProvider" (see https://community.jboss.org/thread/232299)