Unescape escaped filename, bug 39956, r=mscott, a=waterson.

mailnews/base/resources/content/openSaveAttachment.js

@@ -16,6 +16,9 @@
  * Communications Corporation. Portions created by Netscape are
  * Copyright (C) 1998-1999 Netscape Communications Corporation. All
  * Rights Reserved.
+ *
+ * Contributor(s):
+ *   Henrik Gemal <gemal@gemal.dk>
  */
 
 function onLoad()
@@ -28,7 +31,7 @@ function onLoad()
     if (item)
     {
       docnamebox.appendChild(item);
-      item.setAttribute('value', docname);
+      item.setAttribute('value', unescape(docname));
     }
   }
   var saveit = document.getElementById("saveIt");