Heat doesn't work with "deferred_auth_method=trusts"

Issue

• Heat is not able to create stack when deferred_auth_method is set to trusts. When deferred_auth_method is set to password, heat stack creation works without any issue. Following is the debug log while creation of heat stack:

  "POST /v1/19a658782891418da17642f088bc8710/stacks HTTP/1.1" 500 246
  RESP: [500] Content-Type: application/json; charset=UTF-8 Content-Length: 246 X-Openstack-Request-Id: req-93b26229-1e3b-4eb4-9d54-2e9854c2e335 Date: Mon, 09 Jan 2017 14:20:25 GMT Connection: keep-alive 
  RESP BODY: {"explanation": "The server has either erred or is incapable of performing the requested operation.", "code": 500, "error": {"message": "Authorization failed.", "traceback": null, "type": "AuthorizationFailure"}, "title": "Internal Server Error"}
  ERROR: Authorization failed.
  Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/cliff/app.py", line 346, in run_subcommand
  result = cmd.run(parsed_args)
  File "/usr/lib/python2.7/site-packages/cliff/display.py", line 79, in run
  column_names, data = self.take_action(parsed_args)
  File "/usr/lib/python2.7/site-packages/heatclient/osc/v1/stack.py", line 181, in take_action
  stack = client.stacks.create(**fields)['stack']
  File "/usr/lib/python2.7/site-packages/heatclient/v1/stacks.py", line 162, in create
  data=kwargs, headers=headers)
  File "/usr/lib/python2.7/site-packages/keystoneclient/adapter.py", line 182, in post
  return self.request(url, 'POST', **kwargs)
  File "/usr/lib/python2.7/site-packages/heatclient/common/http.py", line 324, in request
  raise exc.from_response(resp)
  HTTPInternalServerError: ERROR: Authorization failed.
  clean_up CreateStack: ERROR: Authorization failed.
  Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/openstackclient/shell.py", line 118, in run
  ret_val = super(OpenStackShell, self).run(argv)
  File "/usr/lib/python2.7/site-packages/cliff/app.py", line 226, in run
  result = self.run_subcommand(remainder)
  File "/usr/lib/python2.7/site-packages/openstackclient/shell.py", line 153, in run_subcommand
  ret_value = super(OpenStackShell, self).run_subcommand(argv)
  File "/usr/lib/python2.7/site-packages/cliff/app.py", line 346, in run_subcommand
  result = cmd.run(parsed_args)
  File "/usr/lib/python2.7/site-packages/cliff/display.py", line 79, in run
  column_names, data = self.take_action(parsed_args)
  File "/usr/lib/python2.7/site-packages/heatclient/osc/v1/stack.py", line 181, in take_action
  stack = client.stacks.create(**fields)['stack']
  File "/usr/lib/python2.7/site-packages/heatclient/v1/stacks.py", line 162, in create
  data=kwargs, headers=headers)
  File "/usr/lib/python2.7/site-packages/keystoneclient/adapter.py", line 182, in post
  return self.request(url, 'POST', **kwargs)
  File "/usr/lib/python2.7/site-packages/heatclient/common/http.py", line 324, in request
  raise exc.from_response(resp)
  HTTPInternalServerError: ERROR: Authorization failed.
  END return value: 1