CORD-1010 Fix Controller, Image, Network, and User model_policies

Change-Id: I42f8771048090666acd9d75ca32b6081a72ce880
diff --git a/xos/synchronizer/steps/sync_instances.py b/xos/synchronizer/steps/sync_instances.py
index bb6c665..640c712 100644
--- a/xos/synchronizer/steps/sync_instances.py
+++ b/xos/synchronizer/steps/sync_instances.py
@@ -88,7 +88,7 @@
 
         # sanity check - make sure model_policy for slice has run
         if ((not instance.slice.policed) or (instance.slice.policed < instance.slice.updated)):
-            raise DeferredException("Instance %s waiting on Slice %s to execute model policies" % (instance, slice.name))
+            raise DeferredException("Instance %s waiting on Slice %s to execute model policies" % (instance, instance.slice.name))
 
         # sanity check - make sure model_policy for all slice networks have run
         for network in instance.slice.ownedNetworks.all():