contrib/win32: license is GPLv2 only

according to Matt Mackall

contrib/win32/ReadMe.html

@@ -98,10 +98,9 b' editor = whatever'
 
     <p>Mercurial is free software; you can redistribute it and/or
       modify it under the terms of the <a
-	href="http://www.gnu.org/copyleft/gpl.html">GNU General Public
-	License</a> as published by the Free Software Foundation; either
-      version 2 of the License, or (at your option) any later
-      version.</p>
+       href="http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt">GNU
+      General Public License version 2</a> as published by the Free
+      Software Foundation.</p>
 
     <p>Mercurial is distributed in the hope that it will be useful,
       but <b>without any warranty</b>; without even the implied