Comment 2 for bug 1193132

Here is a clean stacktrace
File "/opt/stack/new/heat/heat/openstack/common/rpc/amqp.py", line 424, in _process_data
  **args)
File "/opt/stack/new/heat/heat/openstack/common/rpc/dispatcher.py", line 172, in dispatch
  result = getattr(proxyobj, method)(ctxt, **kwargs)
File "/opt/stack/new/heat/heat/engine/service.py", line 53, in wrapped
  return func(self, ctx, *args, **kwargs)
File "/opt/stack/new/heat/heat/engine/service.py", line 185, in list_stacks
  return list(format_stack_details(stacks))
File "/opt/stack/new/heat/heat/engine/service.py", line 182, in format_stack_details
  yield api.format_stack(stack)
File "/opt/stack/new/heat/heat/engine/api.py", line 74, in format_stack
  api.STACK_UPDATED_TIME: timeutils.isotime(stack.updated_time),
File "/opt/stack/new/heat/heat/engine/timestamp.py", line 41, in __get__
  o.refresh(attrs=[self.attribute])
File "/opt/stack/new/heat/heat/db/sqlalchemy/models.py", line 83, in refresh
  session.refresh(self, attrs)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 1167, in refresh
  mapperutil.instance_str(instance))
heat.openstack.common.rpc.amqp InvalidRequestError: Could not refresh instance '<Stack at 0x2c95a90>'