Incorrect usage of _fields method in provider_configuration.py

[Eugene Nikanorov]

When fields filtering is applied, neutron server prints a trace:

 ERROR neutron.api.v2.resource [-] index failed
 TRACE neutron.api.v2.resource Traceback (most recent call last):
 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/api/v2/resource.py", line 84, in resource
 TRACE neutron.api.v2.resource result = method(request=request, **args)
 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/api/v2/base.py", line 273, in index
 TRACE neutron.api.v2.resource return self._items(request, True, parent_id)
 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/api/v2/base.py", line 227, in _items
 TRACE neutron.api.v2.resource obj_list = obj_getter(request.context, **kwargs)
 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/db/servicetype_db.py", line 63, in get_service_providers
 TRACE neutron.api.v2.resource return self.conf.get_service_providers(filters, fields)
 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/services/provider_configuration.py", line 162, in get_service_providers
 TRACE neutron.api.v2.resource return self._fields(res, fields)
 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/services/provider_configuration.py", line 151, in _fields
 TRACE neutron.api.v2.resource return dict(((key, item) for key, item in resource.items()
 TRACE neutron.api.v2.resource AttributeError: 'list' object has no attribute 'items'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47519

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47519
Committed: http://github.com/openstack/neutron/commit/396a0e42755af96d8b96d42ae1bcf4ae4604443d
Submitter: Jenkins
Branch: master

commit 396a0e42755af96d8b96d42ae1bcf4ae4604443d
Author: Eugene Nikanorov <email address hidden>
Date: Fri Sep 20 07:15:38 2013 +0400

    Fix usage of _fields method in provider_configuration.py

    Apply _fields() method to each dict in the list.

    Change-Id: I9357212e203843ffa4a05216d9c79fe8831971a5
    Closes-Bug: #1227971