Correct upgrade.html in faq11.html

$ diff -u openbsd-www/faq/faq11.html faq11.html
--- openbsd-www/faq/faq11.html  Tue May  1 16:35:15 2012
+++ faq11.html  Sun Nov  4 11:34:15 2012
@@ -685,7 +685,7 @@

 The system-wide defaults are in <tt>/etc/X11</tt> and were initially
 loaded from <a href="faq4.html#FilesNeeded">xetcXX.tgz</a>, which is not
-reloaded by the <a href="upgrade50.html">suggested upgrade process</a>,
+reloaded by the <a href="upgrade52.html">suggested upgrade process</a>,
 so if you make system-wide changes, they will persist, but you may need
 to merge those changes into later versions of those files.

$