correcting function name of generator for products of traditional code generator (introduced in 0040bafffdef)

--- a/src/HOL/Product_Type.thy	Tue Jul 13 16:30:13 2010 +0200
+++ b/src/HOL/Product_Type.thy	Tue Jul 13 18:01:42 2010 +0200
@@ -289,7 +289,7 @@
 fun term_of_prod aF aT bF bT (x, y) = HOLogic.pair_const aT bT $ aF x $ bF y;
 *}
 attach (test) {*
-fun term_of_prod aG aT bG bT i =
+fun gen_prod aG aT bG bT i =
   let
     val (x, t) = aG i;
     val (y, u) = bG i