mistral.tests.unit.actions.openstack.test_generator.GeneratorTest.test_generator failed in stable/rocky

With the latest openstacksdk version 0.7.3, mistral.tests.unit.actions.openstack.test_generator.GeneratorTest.test_generator failed with the following error:

Traceback (most recent call last):
  File "mistral/actions/openstack/action_generator/base.py", line 143, in create_actions
    client_method = class_.get_fake_client_method()
  File "mistral/actions/openstack/base.py", line 75, in get_fake_client_method
    return cls._get_client_method(cls._get_fake_client())
  File "mistral/actions/openstack/actions.py", line 827, in _get_fake_client
    return cls._get_client_class()(authenticator=sess.auth)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/senlinclient/v1/client.py", line 28, in __init__
    self.service = self.conn.cluster
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/openstack/service_description.py", line 95, in __get__
    allow_version_hack=True,
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/openstack/config/cloud_region.py", line 470, in get_session_client
    info = client.get_endpoint_data()
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/adapter.py", line 268, in get_endpoint_data
    return self.session.get_endpoint_data(auth or self.auth, **kwargs)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/session.py", line 1130, in get_endpoint_data
    return auth.get_endpoint_data(self, **kwargs)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/identity/base.py", line 271, in get_endpoint_data
    service_catalog = self.get_access(session).service_catalog
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/identity/base.py", line 134, in get_access
    self.auth_ref = self.get_auth_ref(session)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/identity/generic/base.py", line 206, in get_auth_ref
    self._plugin = self._do_create_plugin(session)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/identity/generic/base.py", line 138, in _do_create_plugin
    authenticated=False)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/identity/base.py", line 601, in get_discovery
    authenticated=authenticated)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/discover.py", line 1399, in get_discovery
    disc = Discover(session, url, authenticated=authenticated)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/discover.py", line 498, in __init__
    authenticated=authenticated)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/discover.py", line 101, in get_version_data
    resp = session.get(url, headers=headers, authenticated=authenticated)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/session.py", line 1011, in get
    return self.request(url, 'GET', **kwargs)
  File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/keystoneauth1/session.py", line 699, in request
    if not urllib.parse.urlparse(url).netloc:
  File "/usr/lib/python2.7/urlparse.py", line 143, in urlparse
    tuple = urlsplit(url, scheme, allow_fragments)
  File "/usr/lib/python2.7/urlparse.py", line 182, in urlsplit
    i = url.find(':')
AttributeError: 'NoneType' object has no attribute 'find'
{0} mistral.tests.unit.actions.openstack.test_generator.GeneratorTest.test_generator [0.638071s] ... FAILED

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "mistral/tests/unit/actions/openstack/test_generator.py", line 103, in test_generator
        name=action_name
      File "mistral/tests/unit/base.py", line 141, in _assert_single_item
        return self._assert_multiple_items(items, 1, **props)[0]
      File "mistral/tests/unit/base.py", line 164, in _assert_multiple_items
        "expected=%s, found=%s]" % (props, count, found))
      File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/unittest2/case.py", line 690, in fail
        raise self.failureException(msg)
    AssertionError: Wrong number of items found [props={'name': 'senlin.get_profile'}, expected=1, found=0]

==============================
Failed 1 tests - output below:
==============================

mistral.tests.unit.actions.openstack.test_generator.GeneratorTest.test_generator
--------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):
      File "mistral/tests/unit/actions/openstack/test_generator.py", line 103, in test_generator
        name=action_name
      File "mistral/tests/unit/base.py", line 141, in _assert_single_item
        return self._assert_multiple_items(items, 1, **props)[0]
      File "mistral/tests/unit/base.py", line 164, in _assert_multiple_items
        "expected=%s, found=%s]" % (props, count, found))
      File "/home/gyee/projects/openstack/mistral/.tox/py27/local/lib/python2.7/site-packages/unittest2/case.py", line 690, in fail
        raise self.failureException(msg)
    AssertionError: Wrong number of items found [props={'name': 'senlin.get_profile'}, expected=1, found=0]

The problem seem to have caused by this patch

https://review.opendev.org/#/c/587437/

When 'clustering_default_microversion' is set, it will trigger the Keystone version discovery logic. But in the Mistral unit tests, we are using a fake client so there's no need to exercise the actual HTTP requests.

We'll need to either disable version discovery or mock out the HTTP requests.