Cinder objects base

This patch is to insert the objects code base, currently based
on nova.objects.  It will be later based on
oslo_versionedobjects once it is available.  This is done
to make progress on changing cinder internals to use objects,
since nova.objects and oslo.versionedobjects are similar.

Inserted objects code base into cinder and modified cinder services
to use object-aware serializer.

Change-Id: I42a6cc43da19ca29db4cfb33cbf794afed18f758
Implements: blueprint cinder-objects

cinder/cmd/manage.py

@@ -76,6 +76,7 @@ from cinder import db
 from cinder.db import migration as db_migration
 from cinder.db.sqlalchemy import api as db_api
 from cinder.i18n import _
+from cinder.objects import base as objects_base
 from cinder.openstack.common import log as logging
 from cinder import rpc
 from cinder import utils
@@ -271,7 +272,9 @@ class VolumeCommands(object):
             if not rpc.initialized():
                 rpc.init(CONF)
                 target = messaging.Target(topic=CONF.volume_topic)
-                self._client = rpc.get_client(target)
+                serializer = objects_base.CinderObjectSerializer()
+                self._client = rpc.get_client(target, serializer=serializer)
+
         return self._client
 
     @args('volume_id',