Comment 2 for bug 1870264

Same here.

  File "/usr/share/openstack-dashboard/openstack_dashboard/api/rest/utils.py", line 128, in _wrapped
    data = function(self, request, *args, **kw)
  File "/usr/lib/python2.7/site-packages/magnum_ui/api/rest/magnum.py", line 53, in patch
    request, template_id, **params)
  File "/usr/lib/python2.7/site-packages/magnum_ui/api/magnum.py", line 146, in cluster_template_update
    return magnumclient(request).cluster_templates.update(id, patch)
  File "/usr/lib/python2.7/site-packages/magnumclient/v1/basemodels.py", line 118, in update
    return self._update(self._path(id), patch)
  File "/usr/lib/python2.7/site-packages/magnumclient/common/base.py", line 131, in _update
    resp, resp_body = self.api.json_request(method, url, body=body)
  File "/usr/lib/python2.7/site-packages/magnumclient/common/httpclient.py", line 233, in json_request
    resp, body_iter = self._http_request(url, method, **kwargs)
  File "/usr/lib/python2.7/site-packages/magnumclient/common/httpclient.py", line 213, in _http_request
    error_json = _extract_error_json(body_str, resp)
  File "/usr/lib/python2.7/site-packages/magnumclient/common/httpclient.py", line 63, in _extract_error_json
    content_type = resp.headers.get("Content-Type", "")
AttributeError: HTTPResponse instance has no attribute 'headers'