Error while running tempest tests through Rally

Hi Team,
I am trying to run rally with tempest and was following the link: http://www.mirantis.com/blog/rally-openstack-tempest-testing-made-simpler/

Following is the scenario I am running:

/home/stack/rally/doc/samples/tasks/tempest/single_test.json
{
    "TempestScenario.single_test": [
        {
            "args": {"test_name": "tempest.api.network.test_networks.NetworksTestJSON.test_create_update_delete_network_subnet"},
            "runner": {
                "type": "constant",
                "times": 1,
                "concurrency": 1
            }
        }
    ]
}

Whenever, I run the following commands:

sudo rally -v task start /home/stack/rally/doc/samples/tasks/tempest/single_test.json
or
rally verify start, I am getting the following error:

2014-06-26 19:48:00.078 14103 INFO rally.benchmark.context.users [-] Task 542a0ff5-12f1-4566-8804-38e049b143eb | Completed: Exit context: `users`

================================================================================
Task 542a0ff5-12f1-4566-8804-38e049b143eb is failed.
--------------------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/rally/benchmark/engine.py", line 157, in validate
    self._validate_config_semantic(self.config)
  File "/usr/local/lib/python2.7/dist-packages/rally/utils.py", line 162, in wrapper
    result = f(self, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/rally/benchmark/engine.py", line 147, in _validate_config_semantic
    kwargs)
  File "/usr/local/lib/python2.7/dist-packages/rally/benchmark/engine.py", line 124, in _validate_config_semantic_helper
    users=[user], task=task)
  File "/usr/local/lib/python2.7/dist-packages/rally/benchmark/scenarios/base.py", line 126, in validate
    Scenario._validate_helper(user_validators, user, args, task)
  File "/usr/local/lib/python2.7/dist-packages/rally/benchmark/scenarios/base.py", line 103, in _validate_helper
    result = validator(clients=clients, task=task, **args)
  File "/usr/local/lib/python2.7/dist-packages/rally/benchmark/validation.py", line 237, in tempest_test_exists_validator
    verifier.generate_config_file()
  File "/usr/local/lib/python2.7/dist-packages/rally/verification/verifiers/tempest/tempest.py", line 86, in generate_config_file
    config.TempestConf(self.deploy_id).generate(self.config_file)
  File "/usr/local/lib/python2.7/dist-packages/rally/verification/verifiers/tempest/config.py", line 74, in __init__
    self._load_img()
  File "/usr/local/lib/python2.7/dist-packages/rally/verification/verifiers/tempest/config.py", line 86, in _load_img
    if response.http_status == 200:
AttributeError: 'Response' object has no attribute 'http_status'

Please update if this is a bug or an issue with configuration, my internet is working fine so the above should work as it is trying to fetch the cirros image from internet. I checked the http path manually and it is correct.

Please update as I am stuck with this.

HJowever, running Nova -> boot and delete with the command rally -v task start rally/doc/samples/tasks/nova/boot-and-delete.json is working fine.