some qos tests failing for v2 plugin

test_delete_not_allowed_if_policy_in_use_by_network
test_policy_association_with_admin_network
test_policy_association_with_tenant_network
test_policy_update_association_with_admin_network

eg.
http://logs.openstack.org/88/452888/3/check/gate-tempest-dsvm-networking-midonet-v2-full-ubuntu-xenial-nv/d3afee9/logs/testr_results.html.gz
http://logs.openstack.org/88/452888/3/check/gate-tempest-dsvm-networking-midonet-v2-full-ubuntu-xenial-nv/53816ce/logs/testr_results.html.gz

ft31.15: neutron.tests.tempest.api.test_qos.QosTestJSON.test_policy_association_with_tenant_network[id-1738de5d-0476-4163-9022-5e1b548c208e]_StringException: Empty attachments:
  stderr
  stdout

pythonlogging:'': {{{
2017-04-12 08:53:22,246 30714 INFO [tempest.lib.common.rest_client] Request (QosTestJSON:test_policy_association_with_tenant_network): 201 POST http://10.34.91.61:9696/v2.0/qos/policies 0.283s
2017-04-12 08:53:22,246 30714 DEBUG [tempest.lib.common.rest_client] Request - Headers: {'Content-Type': 'application/json', 'X-Auth-Token': '<omitted>', 'Accept': 'application/json'}
        Body: {"policy": {"name": "test-policy", "description": "test policy", "shared": true}}
    Response - Headers: {u'x-openstack-request-id': 'req-e1a14671-cb8c-42b9-81fe-064bc8691ff1', u'content-type': 'application/json', u'date': 'Wed, 12 Apr 2017 08:53:22 GMT', 'content-location': 'http://10.34.91.61:9696/v2.0/qos/policies', u'content-length': '337', 'status': '201', u'connection': 'close'}
        Body: {"policy": {"name": "test-policy", "rules": [], "tenant_id": "59b2153c5a9e433cb4da88a411e77681", "created_at": "2017-04-12T08:53:22Z", "updated_at": "2017-04-12T08:53:22Z", "revision_number": 1, "shared": true, "project_id": "59b2153c5a9e433cb4da88a411e77681", "id": "4dca3da4-aa2b-4673-8459-d2b336e29a9c", "description": "test policy"}}
2017-04-12 08:53:22,459 30714 INFO [tempest.lib.common.rest_client] Request (QosTestJSON:test_policy_association_with_tenant_network): 201 POST http://10.34.91.61:9696/v2.0/networks 0.212s
2017-04-12 08:53:22,459 30714 DEBUG [tempest.lib.common.rest_client] Request - Headers: {'Content-Type': 'application/json', 'X-Auth-Token': '<omitted>', 'Accept': 'application/json'}
        Body: {"network": {"qos_policy_id": "4dca3da4-aa2b-4673-8459-d2b336e29a9c", "name": "test network"}}
    Response - Headers: {u'x-openstack-request-id': 'req-9fed1fd1-dcbc-4756-b38b-c8471f1aa6a0', u'content-type': 'application/json', u'date': 'Wed, 12 Apr 2017 08:53:22 GMT', 'content-location': 'http://10.34.91.61:9696/v2.0/networks', u'content-length': '469', 'status': '201', u'connection': 'close'}
        Body: {"network":{"status":"ACTIVE","subnets":[],"description":"","admin_state_up":true,"tenant_id":"e46d9a0cc9684a7dbc174997c82f6c11","created_at":"2017-04-12T08:53:22Z","tags":[],"updated_at":"2017-04-12T08:53:22Z","name":"test network","router:external":false,"revision_number":3,"port_security_enabled":true,"shared":false,"project_id":"e46d9a0cc9684a7dbc174997c82f6c11","id":"1298374c-bf73-409e-9c64-8b1af005d7c6","qos_policy_id":"4dca3da4-aa2b-4673-8459-d2b336e29a9c"}}
2017-04-12 08:53:22,539 30714 INFO [tempest.lib.common.rest_client] Request (QosTestJSON:test_policy_association_with_tenant_network): 200 GET http://10.34.91.61:9696/v2.0/networks/1298374c-bf73-409e-9c64-8b1af005d7c6 0.080s
2017-04-12 08:53:22,540 30714 DEBUG [tempest.lib.common.rest_client] Request - Headers: {'Content-Type': 'application/json', 'X-Auth-Token': '<omitted>', 'Accept': 'application/json'}
        Body: None
    Response - Headers: {u'x-openstack-request-id': 'req-e43f5289-333c-44a7-a842-95502c51ca94', u'content-type': 'application/json', u'date': 'Wed, 12 Apr 2017 08:53:22 GMT', 'content-location': 'http://10.34.91.61:9696/v2.0/networks/1298374c-bf73-409e-9c64-8b1af005d7c6', u'content-length': '503', 'status': '200', u'connection': 'close'}
        Body: {"network":{"status":"ACTIVE","subnets":[],"description":"","name":"test network","admin_state_up":true,"tenant_id":"e46d9a0cc9684a7dbc174997c82f6c11","created_at":"2017-04-12T08:53:22Z","tags":[],"updated_at":"2017-04-12T08:53:22Z","provider:network_type":"midonet","router:external":false,"revision_number":3,"port_security_enabled":true,"shared":false,"project_id":"e46d9a0cc9684a7dbc174997c82f6c11","id":"1298374c-bf73-409e-9c64-8b1af005d7c6","qos_policy_id":"4dca3da4-aa2b-4673-8459-d2b336e29a9c"}}
2017-04-12 08:53:22,950 30714 INFO [tempest.lib.common.rest_client] Request (QosTestJSON:test_policy_association_with_tenant_network): 200 PUT http://10.34.91.61:9696/v2.0/networks/1298374c-bf73-409e-9c64-8b1af005d7c6 0.409s
2017-04-12 08:53:22,951 30714 DEBUG [tempest.lib.common.rest_client] Request - Headers: {'Content-Type': 'application/json', 'X-Auth-Token': '<omitted>', 'Accept': 'application/json'}
        Body: {"network": {"qos_policy_id": null}}
    Response - Headers: {u'x-openstack-request-id': 'req-5d63c150-90c1-44f4-bbc5-a3ccad8341fc', u'content-type': 'application/json', u'date': 'Wed, 12 Apr 2017 08:53:22 GMT', 'content-location': 'http://10.34.91.61:9696/v2.0/networks/1298374c-bf73-409e-9c64-8b1af005d7c6', u'content-length': '469', 'status': '200', u'connection': 'close'}
        Body: {"network":{"status":"ACTIVE","subnets":[],"description":"","admin_state_up":true,"tenant_id":"e46d9a0cc9684a7dbc174997c82f6c11","created_at":"2017-04-12T08:53:22Z","tags":[],"updated_at":"2017-04-12T08:53:22Z","name":"test network","router:external":false,"revision_number":4,"port_security_enabled":true,"shared":false,"project_id":"e46d9a0cc9684a7dbc174997c82f6c11","id":"1298374c-bf73-409e-9c64-8b1af005d7c6","qos_policy_id":"4dca3da4-aa2b-4673-8459-d2b336e29a9c"}}
}}}

Traceback (most recent call last):
  File "/opt/stack/new/neutron/neutron/tests/tempest/api/test_qos.py", line 210, in test_policy_association_with_tenant_network
    self._disassociate_network(self.client, network['id'])
  File "/opt/stack/new/neutron/neutron/tests/tempest/api/test_qos.py", line 182, in _disassociate_network
    self.assertIsNone(updated_network['network']['qos_policy_id'])
  File "/usr/local/lib/python2.7/dist-packages/testtools/testcase.py", line 426, in assertIsNone
    self.assertThat(observed, matcher, message)
  File "/usr/local/lib/python2.7/dist-packages/testtools/testcase.py", line 498, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: u'4dca3da4-aa2b-4673-8459-d2b336e29a9c' is not None