Edit qos specs page has an exception

Env: devstack master branch

If click edit qos spec,it will throws an exception.

Exception info:
Internal Server Error: /admin/volume_types/qos_specs/1df7fe9c-d2b8-4111-af04-f74a3813ca7d/key/a/edit/
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 132, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/stack/horizon/horizon/decorators.py", line 36, in dec
    return view_func(request, *args, **kwargs)
  File "/opt/stack/horizon/horizon/decorators.py", line 52, in dec
    return view_func(request, *args, **kwargs)
  File "/opt/stack/horizon/horizon/decorators.py", line 36, in dec
    return view_func(request, *args, **kwargs)
  File "/opt/stack/horizon/horizon/decorators.py", line 84, in dec
    return view_func(request, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 89, in dispatch
    return handler(request, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/views/generic/edit.py", line 206, in get
    return self.render_to_response(self.get_context_data(form=form))
  File "/opt/stack/horizon/openstack_dashboard/dashboards/admin/volume_types/qos_specs/views.py", line 126, in get_context_data
    context['submit_url'] = reverse(self.submit_url, args=args)
  File "/usr/local/lib/python2.7/dist-packages/django/core/urlresolvers.py", line 571, in reverse
    (key, ':'.join(resolved_path)))
NoReverseMatch: u'volume_types' is not a registered namespace inside 'horizon:admin:volumes'