List networks with 'subnets' as filter return 501

[Hongbin Lu]

Description
===========
Neutron return 501 on listing networks with 'subnets=xxx' as filter. This response looks odds for the following reasons:
* Arguably, neutron should return 4xx in this case since it is due to an invalid user input.
* The error message seems to have too much low-level details.

Reproduce
=========

$ TOKEN=$(openstack token issue | awk '/ id /{print $4}')
$ curl -g -i -X GET -H "X-Auth-Token: $TOKEN" 'http://10.0.0.19:9696/v2.0/networks?subnets=11'
HTTP/1.1 501 Not Implemented
Content-Type: application/json
Content-Length: 203
X-Openstack-Request-Id: req-9e3fc06f-ce9b-4e19-bfc0-63cfcec511db
Date: Mon, 05 Feb 2018 22:21:13 GMT

{"NotImplementedError": {"message": "in_() not yet supported for relationships. For a simple many-to-one, use in_() against the set of foreign key values.", "type": "NotImplementedError", "detail": ""}}

Expected
========
Neutron return 4xx error with high-level error message

Actual
======
Neutron return 501 error with low-level error message

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/542485

[Slawek Kaplonski (slaweq)]

This bug has had a related patch abandoned and has been automatically un-assigned due to inactivity. Please re-assign yourself if you are continuing work or adjust the state as appropriate if it is no longer valid.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Slawek Kaplonski (<email address hidden>) on branch: master
Review: https://review.openstack.org/542485
Reason: This review is > 4 weeks 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.

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Bug closed due to lack of activity, please feel free to reopen if needed.