Cleaned up example migration files in docs

docs/ref/migration-operations.txt

@@ -280,7 +280,9 @@ example of using ``RunPython`` to create some initial objects on a ``Country``
 model::
 
     # -*- coding: utf-8 -*-
-    from django.db import models, migrations
+    from __future__ import unicode_literals
+
+    from django.db import migrations, models
 
     def forwards_func(apps, schema_editor):
         # We get the model from the versioned app registry;