deactivating quickcheck narrowing examples to find out if this causes the system error on the current isatest

--- a/src/HOL/Quickcheck_Examples/ROOT.ML	Wed Jul 18 20:59:02 2012 +0200
+++ b/src/HOL/Quickcheck_Examples/ROOT.ML	Thu Jul 19 12:01:05 2012 +0200
@@ -9,7 +9,7 @@
   "Needham_Schroeder_Guided_Attacker_Example",
   "Needham_Schroeder_Unguided_Attacker_Example"
 ];
-
+(*
 if getenv "ISABELLE_GHC" = "" then ()
 else use_thy "Quickcheck_Narrowing_Examples";
-
+*)