Description of problem:
heat_tempest_plugin.tests.api.test_heat_api.softwareconfig_show_deployment_metadata.test_request[id-d26d1ae4-4924-11e8-842f-0ed5f89f718b] test fails with this callstack:

testtools.testresult.real._StringException: Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/gabbi/suitemaker.py", line 95, in do_test
    return test_method(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/gabbi/case.py", line 94, in wrapper
    func(self)
  File "/usr/lib/python3.6/site-packages/gabbi/case.py", line 148, in test_request
    self._run_test()
  File "/usr/lib/python3.6/site-packages/gabbi/case.py", line 555, in _run_test
    self._assert_response()
  File "/usr/lib/python3.6/site-packages/gabbi/case.py", line 193, in _assert_response
    self._test_status(self.test_data['status'], self.response['status'])
  File "/usr/lib/python3.6/site-packages/gabbi/case.py", line 610, in _test_status
    self.assert_in_or_print_output(observed_status, statii)
  File "/usr/lib/python3.6/site-packages/gabbi/case.py", line 671, in assert_in_or_print_output
    self.fail(msg)
  File "/usr/lib/python3.6/site-packages/unittest2/case.py", line 693, in fail
    raise self.failureException(msg)
AssertionError: '400' not found in ['200'], response:
{
  "code": 400,
  "title": "Bad Request",
  "explanation": "The server could not comply with the request since it is either malformed or otherwise incorrect.",
  "error": {
    "type": "HTTPBadRequest",
    "traceback": null,
    "message": "The server could not comply with the request since it is either malformed or otherwise incorrect."
  }
}

http://staging-jenkins2-qe-playground.usersys.redhat.com/view/DFG/view/cloud_apps/view/heat/job/DFG-cloud_apps-heat-15_director-rhel-virthost-3cont_1comp_3ceph-ipv4-geneve-poc/12/testReport/heat_tempest_plugin.tests.api.test_heat_api/softwareconfig_show_deployment_metadata/test_request_id_d26d1ae4_4924_11e8_842f_0ed5f89f718b_/

Version-Release number of selected component (if applicable):


How reproducible:
Run heat regression tempest job
http://staging-jenkins2-qe-playground.usersys.redhat.com/view/DFG/view/cloud_apps/view/heat/job/DFG-cloud_apps-heat-15_director-rhel-virthost-3cont_1comp_3ceph-ipv4-geneve-poc/

Steps to Reproduce:
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Actual results:


Expected results:


Additional info: