Miss 'next' field at list response

[hongbin]

On 'list' operations of containers/images/services, the 'next' field is missing from the response.

Request:

$ TOKEN=$(openstack token issue | awk '/ id /{print $4}')
$ curl -g -i -X GET http://192.168.11.4:9517/v1/containers/?limit=1 -H -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: $TOKEN"

Response:

{
    "containers": [...]
}

Correct response:

{
    "containers": [...],
    "next": "http://192.168.11.4:9517/v1/containers?marker=xxx&....."
}

I think here is the reason why the 'next' field is missing:
* In here https://github.com/openstack/zun/blob/master/zun/api/controllers/base.py#L30 , it read the 'fields' variable to generate response
* The 'next' field is declared in https://github.com/openstack/zun/blob/master/zun/api/controllers/v1/collection.py#L23 , but it was incorrectly override at https://github.com/openstack/zun/blob/master/zun/api/controllers/v1/containers.py#L59

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/455618

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/455618
Committed: https://git.openstack.org/cgit/openstack/zun/commit/?id=b47890589e0d8f68f3afa03e338eee91b49ccdf1
Submitter: Jenkins
Branch: master

commit b47890589e0d8f68f3afa03e338eee91b49ccdf1
Author: Feng Shengqin <email address hidden>
Date: Tue Apr 11 17:04:23 2017 +0800

    Miss 'next' field at list response

    Change-Id: Id8510fa66e2407404e82cac73fa9843ba067eee5
    Closes-Bug: #1681537