Updated instructions on Boost sandbox CVS

[SVN r23668]

more/mailing_lists.htm

@@ -264,7 +264,7 @@
 
     <blockquote>
       <p>
-      &nbsp;<code>:pserver:anonymous@cvs.boost-sandbox.sourceforge.net:/cvsroot/boost-sandbox</code></p>
+      &nbsp;<code>:pserver:anonymous@cvs.sourceforge.net:/cvsroot/boost-sandbox</code></p>
     </blockquote>
     <hr>