retain output, which is required for non-existent JRE, for example (cf. b455e4f42c04);

--- a/Admin/MacOS/App1/script	Tue Sep 27 00:03:11 2011 +0200
+++ b/Admin/MacOS/App1/script	Tue Sep 27 14:17:40 2011 +0200
@@ -106,8 +106,7 @@
   ( "$ISABELLE_TOOL" emacs "${EMACS_OPTIONS[@]}" "$@" ) > "$OUTPUT" 2>&1
   RC=$?
 else
-  rm -f "$OUTPUT" && touch "$OUTPUT"
-  "$ISABELLE_TOOL" jedit "$@"
+  ( "$ISABELLE_TOOL" jedit "$@" ) > "$OUTPUT" 2>&1
   RC=$?
 fi