changed "list-fn" to "listfn"

--- a/src/ZF/ROOT.ML	Wed Oct 06 10:33:33 1993 +0100
+++ b/src/ZF/ROOT.ML	Wed Oct 06 14:19:39 1993 +0100
@@ -67,7 +67,7 @@
 
 use     "fin.ML";
 use     "list.ML";
-use_thy "list-fn";
+use_thy "listfn";
 
 (*printing functions are inherited from FOL*)
 print_depth 8;