7147407: remove never used debug code in DnsClient.java

Reviewed-by: vinnie

src/share/classes/com/sun/jndi/dns/DnsClient.java

 /*
- * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -622,11 +622,7 @@ public class DnsClient {
 
     //-------------------------------------------------------------------------
 
-    private static boolean debug = false;
-
-    public static void setDebug(boolean flag) {
-        debug = flag;
-    }
+    private static final boolean debug = false;
 
     private static void dprint(String mess) {
         if (debug) {