fix virtual service retry docs (#3416)

Signed-off-by: Rama Chavali <rama.rao@salesforce.com>

Author: ramaraochavali

networking/v1alpha3/virtual_service.pb.go

@@ -1307,7 +1307,7 @@ message HTTPRetry {
   // For example, if a connection is reset, Istio will translate this to 503 for it's response.
   // However, the destination did not return a 503 error, so this would not match `"503"` (it would, however, match `"reset"`).
   //
-  // If not specified, this defaults to `connect-failure,refused-stream,unavailable,cancelled,503`.
+  // If not specified, this defaults to `connect-failure,refused-stream,unavailable,cancelled`.
   string retry_on = 3;
 
   // Flag to specify whether the retries should retry to other localities.