CORD-1053 fix attribute not being saved

Change-Id: I5ebb7f777ca1eb71329dc1e1f1b43f1c679448fd
diff --git a/xos/synchronizer/steps/sync_onos_netcfg.py b/xos/synchronizer/steps/sync_onos_netcfg.py
index 056c1be..10f1c84 100644
--- a/xos/synchronizer/steps/sync_onos_netcfg.py
+++ b/xos/synchronizer/steps/sync_onos_netcfg.py
@@ -52,7 +52,7 @@
                 ta.save()
         else:
             logger.info("saving autogenerated config %s" % name)
-            ta = TenantAttribute(tenant=tenant, name=name, value=value)
+            ta = model_accessor.create_obj(TenantAttribute, tenant=tenant, name=name, value=value)
             ta.save()
 
     # This function currently assumes a single Deployment and Site