Unable to create router when the external network is specified

[wei.ying]

Env: devstack master branch

Steps to reproduce:

1. Go to Project/Network Routers panel
2. Click Create Router button
3. Choose an external network and on form submit

Error info:
INFO openstack_dashboard.dashboards.project.routers.forms Failed to create router: 'CreateForm' object has no attribute 'ext_gw_mode_supported'
ERROR django.request Internal Server Error: /project/routers/create/
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 249, in _legacy_get_response
    response = self._get_response(request)
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 185, 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 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/views/generic/base.py", line 88, in dispatch
    return handler(request, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/django/views/generic/edit.py", line 183, in post
    return self.form_valid(form)
  File "/opt/stack/horizon/horizon/forms/views.py", line 188, in form_valid
    exceptions.handle(self.request)
  File "/opt/stack/horizon/horizon/exceptions.py", line 351, in handle
    six.reraise(exc_type, exc_value, exc_traceback)
  File "/opt/stack/horizon/horizon/forms/views.py", line 185, in form_valid
    handled = form.handle(self.request, form.cleaned_data)
  File "/opt/stack/horizon/openstack_dashboard/dashboards/project/routers/forms.py", line 141, in handle
    if exc.status_code == 409:
AttributeError: 'exceptions.AttributeError' object has no attribute 'status_code'
ERROR django.server "POST /project/routers/create/ HTTP/1.1" 500 145275

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/521238

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/521238
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=de9f03c9ab3d95ce2e21a22822f0f3902f489760
Submitter: Zuul
Branch: master

commit de9f03c9ab3d95ce2e21a22822f0f3902f489760
Author: wei.ying <email address hidden>
Date: Sat Nov 18 15:40:41 2017 +0800

    Unable to create router when the external network is specified

    In project create router form, when creating router with the external
    network, there is no need to determine "ext_gw_mode_supported" since
    the "ext_gw-mode" has been checked when the form is initialized.
    So, we need to delete it since it's also undefined.

    Change-Id: I6dc221638ccda2a8819776679735685cb3c61d56
    Closes-Bug:#1733047

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/horizon 13.0.0.0b2 development milestone.