Confirm resize instance will report a 409 error,when another instance is being created

[Tue Dec 12 16:31:08.031005 2017] [:error] [pid 88] Internal Server Error: /project/instances/
[Tue Dec 12 16:31:08.031056 2017] [:error] [pid 88] Traceback (most recent call last):
[Tue Dec 12 16:31:08.031069 2017] [:error] [pid 88] File "/usr/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response
[Tue Dec 12 16:31:08.031079 2017] [:error] [pid 88] response = wrapped_callback(request, *callback_args, **callback_kwargs)
[Tue Dec 12 16:31:08.031086 2017] [:error] [pid 88] File "horizon/decorators.py", line 36, in dec
[Tue Dec 12 16:31:08.031092 2017] [:error] [pid 88] File "horizon/decorators.py", line 84, in dec
[Tue Dec 12 16:31:08.031098 2017] [:error] [pid 88] File "horizon/decorators.py", line 52, in dec
[Tue Dec 12 16:31:08.031103 2017] [:error] [pid 88] File "horizon/decorators.py", line 36, in dec
[Tue Dec 12 16:31:08.031110 2017] [:error] [pid 88] File "horizon/decorators.py", line 84, in dec
[Tue Dec 12 16:31:08.031116 2017] [:error] [pid 88] File "/usr/lib/python2.7/site-packages/django/views/generic/base.py", line 71, in view
[Tue Dec 12 16:31:08.031123 2017] [:error] [pid 88] return self.dispatch(request, *args, **kwargs)
[Tue Dec 12 16:31:08.031130 2017] [:error] [pid 88] File "/usr/lib/python2.7/site-packages/django/views/generic/base.py", line 89, in dispatch
[Tue Dec 12 16:31:08.031137 2017] [:error] [pid 88] return handler(request, *args, **kwargs)
[Tue Dec 12 16:31:08.031143 2017] [:error] [pid 88] File "horizon/tables/views.py", line 288, in post
[Tue Dec 12 16:31:08.031149 2017] [:error] [pid 88] File "horizon/tables/views.py", line 223, in get
[Tue Dec 12 16:31:08.031157 2017] [:error] [pid 88] File "horizon/tables/views.py", line 214, in construct_tables
[Tue Dec 12 16:31:08.031164 2017] [:error] [pid 88] File "horizon/tables/views.py", line 129, in handle_table
[Tue Dec 12 16:31:08.031171 2017] [:error] [pid 88] File "horizon/tables/base.py", line 1783, in maybe_handle
[Tue Dec 12 16:31:08.031193 2017] [:error] [pid 88] File "horizon/tables/base.py", line 1616, in take_action
[Tue Dec 12 16:31:08.031200 2017] [:error] [pid 88] File "openstack_dashboard/dashboards/project/instances/tables.py", line 621, in single
[Tue Dec 12 16:31:08.031209 2017] [:error] [pid 88] File "/usr/share/openstack-dashboard/openstack_dashboard/api/nova.py", line 639, in server_confirm_resize
[Tue Dec 12 16:31:08.031216 2017] [:error] [pid 88] novaclient(request).servers.confirm_resize(instance_id)
[Tue Dec 12 16:31:08.031222 2017] [:error] [pid 88] File "novaclient/v2/servers.py", line 1755, in confirm_resize
[Tue Dec 12 16:31:08.031228 2017] [:error] [pid 88] File "novaclient/v2/servers.py", line 2218, in _action
[Tue Dec 12 16:31:08.031235 2017] [:error] [pid 88] File "novaclient/v2/servers.py", line 2229, in _action_return_resp_and_body
[Tue Dec 12 16:31:08.031241 2017] [:error] [pid 88] File "/usr/lib/python2.7/site-packages/keystoneauth1/adapter.py", line 294, in post
[Tue Dec 12 16:31:08.031263 2017] [:error] [pid 88] return self.request(url, 'POST', **kwargs)
[Tue Dec 12 16:31:08.031270 2017] [:error] [pid 88] File "novaclient/client.py", line 83,...

Fix proposed to branch: master
Review: https://review.openstack.org/527354

Change abandoned by Ivan Kolodyazhny (<email address hidden>) on branch: master
Review: https://review.openstack.org/527354
Reason: This review is > 4 months without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.