Remove DictCompat from mapping objects

HostMapping and InstanceMapping had DictCompat inheritance solely
because of bug 1474952. This bug was fixed back in o.vo 0.6.0, so this
inheritance can be removed. These objects did not use dict syntax
anywhere, so accessors did not have to be changed over.

Change-Id: I1bde23f2ffeb8ed562e8c3f195a0cfe75fb455b3
Partially-Implements: bp rm-object-dict-compat-newton

nova/objects/host_mapping.py

@@ -10,7 +10,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from oslo_versionedobjects import base as ovo
 from sqlalchemy.orm import joinedload
 
 from nova.db.sqlalchemy import api as db_api
@@ -27,10 +26,8 @@ def _cell_id_in_updates(updates):
         updates["cell_id"] = cell_mapping_obj.id
 
 
-# NOTE(danms): Maintain Dict compatibility because of ovo bug 1474952
 @base.NovaObjectRegistry.register
-class HostMapping(base.NovaTimestampObject, base.NovaObject,
-                  ovo.VersionedObjectDictCompat):
+class HostMapping(base.NovaTimestampObject, base.NovaObject):
     # Version 1.0: Initial version
     VERSION = '1.0'
 

nova/objects/instance_mapping.py

@@ -10,7 +10,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from oslo_versionedobjects import base as ovo
 from sqlalchemy.orm import joinedload
 
 from nova.db.sqlalchemy import api as db_api
@@ -22,10 +21,8 @@ from nova.objects import cell_mapping
 from nova.objects import fields
 
 
-# NOTE(danms): Maintain Dict compatibility because of ovo bug 1474952
 @base.NovaObjectRegistry.register
-class InstanceMapping(base.NovaTimestampObject, base.NovaObject,
-                      ovo.VersionedObjectDictCompat):
+class InstanceMapping(base.NovaTimestampObject, base.NovaObject):
     # Version 1.0: Initial version
     VERSION = '1.0'