third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/python/google/protobuf/pyext/map_container.h

Index: third_party/protobuf/python/google/protobuf/pyext/map_container.h
diff --git a/third_party/protobuf/python/google/protobuf/pyext/map_container.h b/third_party/protobuf/python/google/protobuf/pyext/map_container.h
index fbd6713f7319da73e7c45e79c7940f00bb89526c..615657b03b8df576bc0dbf9fce3333d79de65c92 100644
--- a/third_party/protobuf/python/google/protobuf/pyext/map_container.h
+++ b/third_party/protobuf/python/google/protobuf/pyext/map_container.h
@@ -112,16 +112,10 @@ struct MessageMapContainer : public MapContainer {
   PyObject* message_dict;
 };
 
-#if PY_MAJOR_VERSION >= 3
-  extern PyObject *MessageMapContainer_Type;
-  extern PyType_Spec MessageMapContainer_Type_spec;
-  extern PyObject *ScalarMapContainer_Type;
-  extern PyType_Spec ScalarMapContainer_Type_spec;
-#else
-  extern PyTypeObject MessageMapContainer_Type;
-  extern PyTypeObject ScalarMapContainer_Type;
-#endif
+bool InitMapContainers();
 
+extern PyTypeObject* MessageMapContainer_Type;
+extern PyTypeObject* ScalarMapContainer_Type;
 extern PyTypeObject MapIterator_Type;  // Both map types use the same iterator.
 
 // Builds a MapContainer object, from a parent message and a