Correct comments

source/blender/python/intern/bpy_driver.c

@@ -259,7 +259,7 @@ float BPY_driver_exec(ChannelDriver *driver, const float evaltime)
 	}
 
 	/* add target values to a dict that will be used as '__locals__' dict */
-	driver_vars = PyDict_New(); // XXX do we need to decref this?
+	driver_vars = PyDict_New();
 	for (dvar = driver->variables.first, i = 0; dvar; dvar = dvar->next) {
 		PyObject *driver_arg = NULL;
 		float tval = 0.0f;