gateway device UT failure

the following tests are failing.

test_create_gateway_device_hw_vtep
test_list_gateway_devices
test_show_gateway_device_hw_vtep

eg. http://logs.openstack.org/87/199387/75/check/gate-networking-midonet-python27-ubuntu-xenial/48614e7/testr_results.html.gz

ft1.20: midonet.neutron.tests.unit.test_extension_gateway_device.GatewayDeviceTestCaseWithML2.test_create_gateway_device_hw_vtep_StringException: stderr: {{{
Traceback (most recent call last):
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tox/py27/local/lib/python2.7/site-packages/eventlet/hubs/hub.py", line 457, in fire_timers
    timer()
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tox/py27/local/lib/python2.7/site-packages/eventlet/hubs/timer.py", line 58, in __call__
    cb(*args, **kw)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tox/py27/local/lib/python2.7/site-packages/eventlet/greenthread.py", line 214, in main
    result = function(*args, **kwargs)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tox/py27/local/lib/python2.7/site-packages/oslo_concurrency/lockutils.py", line 271, in inner
    return f(*args, **kwargs)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/plugins/ml2/ovo_rpc.py", line 98, in dispatch_events
    obj = self._obj_class.get_object(context, id=resource_id)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/objects/base.py", line 441, in get_object
    return cls._load_object(context, db_obj)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/objects/base.py", line 399, in _load_object
    obj.from_db_object(db_obj)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/objects/subnet.py", line 248, in from_db_object
    super(Subnet, self).from_db_object(db_obj)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/objects/base.py", line 343, in from_db_object
    self.load_synthetic_db_fields(db_obj)
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/objects/base.py", line 592, in load_synthetic_db_fields
    foreign_keys = objclass.foreign_keys.get(clsname)
AttributeError: type object 'Route' has no attribute 'foreign_keys'
}}}

Traceback (most recent call last):
  File "/home/jenkins/workspace/gate-networking-midonet-python27-ubuntu-xenial/.tmp/tmp.NahFG7mu4Z/openstack/neutron/neutron/tests/base.py", line 115, in func
    return f(self, *args, **kwargs)
  File "midonet/neutron/tests/unit/test_extension_gateway_device.py", line 460, in test_create_gateway_device_hw_vtep
    with self.gateway_device_type_hw_vtep() as gw_dev:
  File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
    return self.gen.next()
  File "midonet/neutron/tests/unit/test_extension_gateway_device.py", line 74, in gateway_device_type_hw_vtep
    tunnel_ips)
  File "midonet/neutron/tests/unit/test_extension_gateway_device.py", line 104, in _make_gateway_device_hw_vtep
    raise webob.exc.HTTPClientError(code=res.status_int)
webob.exc.HTTPClientError: The server could not comply with the request since it is either malformed or otherwise incorrect.