CORD-2274: Use defer_sync to defer synchronization in case of error

Change-Id: I08bdff0385d5ef956d3af8e53c3c5f694c9332f9
diff --git a/xos/synchronizer/steps/sync_vspgwutenant.py b/xos/synchronizer/steps/sync_vspgwutenant.py
index 2580e6c..838cf02 100644
--- a/xos/synchronizer/steps/sync_vspgwutenant.py
+++ b/xos/synchronizer/steps/sync_vspgwutenant.py
@@ -36,7 +36,6 @@
     def __init__(self, *args, **kwargs):
         super(SyncVSPGWUTenant, self).__init__(*args, **kwargs)
 
-
     def get_extra_attributes(self, o):
 
         scenario = self.get_scenario()
@@ -222,6 +221,7 @@
         except Exception:
             ip_address = "error"
             self.log.error("Failed to fetch parameter", parameter = parameter, network_name = network_name)
+            self.defer_sync("Waiting for parameters to become available")
 
         return ip_address
 
@@ -233,4 +233,4 @@
     def get_instance_id(self, serviceinstance):
         instances = serviceinstance.objects.all()
         instance_id = instances[0].instance_id
-        return instance_id
\ No newline at end of file
+        return instance_id