Fixed changes requested

Author: atlas

openwisp_controller/config/migrations/0056_ow_zt-to-global.py

@@ -3,7 +3,7 @@
 
 def change_owzt_to_global(apps, schema_editor):
     Template = apps.get_model('config', 'Template')
-    for template in Template.objects.all():
+    for template in Template.objects.filter(type='vpn',vpn__backend='openwisp_controller.vpn_backends.ZeroTier'):
         config = json.loads(template.config)
         if 'zerotier' in config:
             for item in config.get('zerotier',[]):
@@ -15,4 +15,5 @@ class Migration(migrations.Migration):
 
     operations = [
         migrations.RunPython(change_owzt_to_global, reverse_code=migrations.RunPython.noop)
-    ]
+    ]
+