ipatests: remove test_ordering
    
    The test_integration/test_ordering.py is a test for pytest_sourceorder
    plugin which is not part of freeipa project, it is not an integration test.
    
    The up to date version of this test is available at project repository:
    https://pagure.io/python-pytest-sourceorder/blob/master/f/test_sourceorder.py
    
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>