Policy is not initialized in designate-sink

Policy is not initialized in designate-sink, resulting in failures to any policy.enforce() call similar to:

2014-09-08 10:11:58.360 INFO designate.policy [-] Policy check failed for rule 'all_tenants' on target {}
2014-09-08 10:11:58.361 ERROR oslo.messaging.notify.dispatcher [-] Exception during message handling
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher Traceback (most recent call last):
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/usr/local/lib/python2.7/dist-packages/oslo/messaging/notify/dispatcher.py", line 85, in _dispatch_and_handle_error
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher return self._dispatch(incoming.ctxt, incoming.message)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/usr/local/lib/python2.7/dist-packages/oslo/messaging/notify/dispatcher.py", line 121, in _dispatch
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher metadata)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/sink/service.py", line 114, in info
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher handler.process_notification(context, event_type, payload)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/notification_handler/nova.py", line 60, in process_notification
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher resource_type='instance')
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/notification_handler/base.py", line 122, in _create
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher domain = self.get_domain(cfg.CONF[self.name].domain_id)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/notification_handler/base.py", line 80, in get_domain
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher context = DesignateContext.get_admin_context(all_tenants=True)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/context.py", line 104, in get_admin_context
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher return cls(None, **kwargs)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/context.py", line 57, in __init__
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher self.all_tenants = all_tenants
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/context.py", line 128, in all_tenants
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher policy.check('all_tenants', self)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher File "/opt/stack/designate/designate/policy.py", line 86, in check
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher result = _ENFORCER.enforce(rule, target, creds, do_raise, exc)
2014-09-08 10:11:58.361 TRACE oslo.messaging.notify.dispatcher AttributeError: 'NoneType' object has no attribute 'e