chore(qa): use OpenJPA 2 in old-engine-tests
chore(qa): use OpenJPA 2 in old-engine-tests

- during 7.13 development, we switched to testing against OpenJPA 2 instead
  of OpenJPA 1. In the old-engine test suite, we had to keep the OpenJPA1
  dependency, because we run the tests of the old engine version there
  (and switching to OpenJPA 2 required some code changes). With 7.13.0
  released, we can switch to OpenJPA 2 in the test suite

related to CAM-11872

langfr/camunda-bpm-platform,camunda/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,camunda/camunda-bpm-platform,camunda/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform,camunda/camunda-bpm-platform,langfr/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,camunda/camunda-bpm-platform,camunda/camunda-bpm-platform,ingorichtsmeier/camunda-bpm-platform,langfr/camunda-bpm-platform