return error if relayed node is an InetClient

pro/logic/relays.go

@@ -123,6 +123,9 @@ func ValidateRelay(relay models.RelayRequest, update bool) error {
 		if relayedNode.IsInternetGateway {
 			return errors.New("cannot relay an internet gateway (" + relayedNodeID + ")")
 		}
+		if relayedNode.InternetGwID != "" {
+			return errors.New("cannot relay an internet client (" + relayedNodeID + ")")
+		}
 		if relayedNode.IsFailOver {
 			return errors.New("cannot relay a failOver (" + relayedNodeID + ")")
 		}