Após as mudanças, comecei a ver esse erro no log.
ERROR: WELD-000019: Error destroying an instance org.hibernate.ejb.EntityManagerImpl@11ffdb3a of Producer Method [EntityManager] with qualifiers [@Any @Default] declared as [[BackedAnnotatedMethod] @Produces @RequestScoped public br.com.caelum.livraria.dao.JPAUtil.getEntityManager()]