Fix inconsistency in CADF initiator name field

For CADF messages, keystone stores the initiator username in the
'initiator.username' field, and keystonemiddleware stores it in the
'initiator.name' field[1].

CADF specs[2] says it should be initiator:name, so make it consistent.

Keep the initiator.username field so as not to break existing
deployments.

[1] https://opendev.org/openstack/keystonemiddleware/src/branch/stable/2023.2/keystonemiddleware/audit/_api.py#L290
[2] https://www.dmtf.org/sites/default/files/standards/documents/DSP2038_1.1.0.pdf#page=14

Closes-Bug: #2063321

Change-Id: I69d662dd3c0e70d2a614655b62dd9655c438fc0b

keystone/notifications.py

@@ -833,6 +833,8 @@ def _add_username_to_initiator(initiator):
         return initiator
     try:
         user_ref = PROVIDERS.identity_api.get_user(initiator.user_id)
+        # NOTE(jake): name should be used, username kept for compatibility
+        initiator.name = user_ref['name']
         initiator.username = user_ref['name']
     except (exception.UserNotFound, AttributeError):
         # Either user not found or no user_id, move along

keystone/tests/unit/common/test_notifications.py

@@ -1156,7 +1156,7 @@ class CadfNotificationsWrapperTestCase(test_v3.RestfulTestCase):
                     'typeURI': 'service/security/account/user',
                     'host': {'address': 'localhost'},
                     'id': 'openstack:0a90d95d-582c-4efb-9cbc-e2ca7ca9c341',
-                    'username': u'admin'
+                    'name': 'admin'
                 },
                 'target': {
                     'typeURI': 'service/security/account/user',
@@ -1211,6 +1211,7 @@ class CadfNotificationsWrapperTestCase(test_v3.RestfulTestCase):
         self.assertEqual(len(self._notifications), 1)
         note = self._notifications.pop()
         initiator = note['initiator']
+        self.assertEqual(self.user['name'], initiator.name)
         self.assertEqual(self.user['name'], initiator.username)
 
     def test_v3_authenticate_user_name_and_domain_id(self):