This upstream patch addresses Launchpad bug 1255441. Although it's been
addressed in Kilo, the patch below is still not yet released for Juno.

commit a8c7db5b9d9bba44660de3c7a64295f9f318b63a
Author: Assaf Muller <email address hidden>
Date: Wed Apr 1 09:38:21 2015 -0400

    Remove "Arguments dropped when creating context" logging

    This log was previously reduced from warning to debug.
    Cinder removed it entirely in:
    https://bugs.launchpad.net/cinder/+bug/1329156

    The root cause is this:
    Agent heartbeats use an admin context. The context is serialized
    with its to_dict method, which exposes 'tenant' and 'project_name'
    (These are properties of the class that are calculated from other
    attributes). In the controller, this dict is used to initialize a
    ContextBase, which does not accept tenant and project_name as arguments,
    de facto sending those values as key word arguments.

    We can either handle 'tenant' and 'project_name' specially, fix
    it any other way, or drop the logging entirely. Is this logging
    ever useful?

    Change-Id: Ifd51b62bae7b96de44f04836015d2ed939bcb650
    Closes-Bug: #1255441

--- neutron-2014.2.2/neutron/context.py	2015-02-05 07:45:33.000000000 -0800
+++ new/neutron/context.py	2015-10-15 09:34:13.121138271 -0700
@@ -76,12 +76,6 @@
         if overwrite or not hasattr(local.store, 'context'):
             local.store.context = self
 
-        # Log only once the context has been configured to prevent
-        # format errors.
-        if kwargs:
-            LOG.debug(_('Arguments dropped when creating '
-                        'context: %s'), kwargs)
-
     @property
     def project_id(self):
         return self.tenant
--- neutron-2014.2.2/neutron/tests/unit/test_neutron_context.py	2015-02-05 07:45:26.000000000 -0800
+++ new/neutron/tests/unit/test_neutron_context.py	2015-10-16 12:51:55.872425513 -0700
@@ -41,11 +41,6 @@
         self.assertIsNone(ctx.tenant_name)
         self.assertIsNone(ctx.auth_token)
 
-    def test_neutron_context_create_logs_unknown_kwarg(self):
-        with mock.patch.object(context.LOG, 'debug') as mock_log:
-            context.Context('user_id', 'tenant_id', foo=None)
-        self.assertEqual(mock_log.call_count, 1)
-
     def test_neutron_context_create_with_name(self):
         ctx = context.Context('user_id', 'tenant_id',
                               tenant_name='tenant_name', user_name='user_name')