Comment 3 for bug 1685822

Hi Ying. Thanks for your comments.
When I upgraded the local environment, the problem didn't come back.

I'm not sure why the following method was not called again when the edit extra specs form was submitted.
But If the form_invalid function[1] is called, it will cause error. Due to the method '_populate_context has then redefined in [2].

[1] https://github.com/openstack/horizon/blob/master/openstack_dashboard/dashboards/admin/volume_types/extras/views.py#L123.
[2] https://review.openstack.org/#/c/337703/7/horizon/forms/views.py