Comment 2 for bug 1780503

I was able to recreate this. I didn't verify this with rabbit directly, but I did see the messages logged via python. I used the following configuration in keystone.conf (using devstack):

```
[DEFAULT]
notification_opt_out = ""

[oslo_messaging_notifications]
driver = log
```

I created a token as the administrator:

ubuntu|devstack|keystone >>> openstack --os-cloud devstack-admin token issue
+------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field | Value |
+------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| expires | 2018-08-01T19:55:52+0000 |
| id | gAAAAABbYgI4DieU2QDc79b6kVTeywh0ifYhQQFforMOSyNOTYL6bWveY7WsqyEYGDYOosBxpF69V89aj0b6ZYiB067KjY0OXVfbSZjohuqW2l6Jkcy-mAq4K8Vp6-6oe_-jcDYeMD0h2wDxd7OwJuIZKl0EXaDgFtzkk_Pt2N4MSJ0uQyIluDk |
| project_id | da1acf5e6e3c4457bc97e332ab23c8f3 |
| user_id | 383d315c51c041cab1411b21989d3f68 |
+------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

The resulting notification in the logs doesn't include the user ID anywhere:

Aug 01 18:55:52 devstack <email address hidden>[14999]: INFO oslo.messaging.notification.identity.authenticate [None req-abce0d65-af48-4a60-9a67-6b39d3590cbc None None] {"event_type": "identity.authenticate", "timestamp": "2018-08-01 18:55:52.897045", "payload": {"typeURI": "http://schemas.dmtf.org/cloud/audit/1.0/event", "initiator": {"typeURI": "service/security/account/user", "host": {"agent": "openstacksdk/0.17.1 keystoneauth1/3.10.0 python-requests/2.19.1 CPython/2.7.15rc1", "address": "192.168.1.202"}, "id": "89d7d8e1-0889-5484-9ea4-21f8a66d2df9"}, "target": {"typeURI": "service/security/account/user", "id": "37c56d47-110c-5c65-bebc-298c85cb75f4"}, "observer": {"typeURI": "service/security", "id": "81f6210c355b49aab537a92c21108df1"}, "eventType": "activity", "eventTime": "2018-08-01T18:55:52.831833+0000", "action": "authenticate", "outcome": "success", "id": "81a27074-5e4d-538d-9fff-dca598a2c73a"}, "priority": "INFO", "publisher_id": "identity.devstack", "message_id": "b381953a-cedc-4392-8226-7c90ef7e2c0c"}