Fixing PONPort modeling

Change-Id: I9875f11fa9496fec4e749c09e18d20df9683c770
diff --git a/xos/synchronizer/models/volt.xproto b/xos/synchronizer/models/volt.xproto
index 651957e..a58b696 100644
--- a/xos/synchronizer/models/volt.xproto
+++ b/xos/synchronizer/models/volt.xproto
@@ -56,6 +56,6 @@
 
     required string name = 1 [db_index = True, null = False, blank = False];
     required manytoone volt_device->OLTDevice:ports = 2 [db_index = True, null = False, blank = False];
-    required string port_id = 3 [help_text = "Port ID (Feedback State)", max_length = 254, null = False, db_index = False, blank = False, tosca_key = True];
+    required string port_id = 3 [help_text = "Port ID (Feedback State)", max_length = 254, null = False, db_index = False, blank = False];
     required int32 s_tag = 4 [help_text = "S Tag", null = False, db_index = False, blank = False];
 }