[dev] Documentation Update (Cyrus IMAP performance tuning link)

[Matt Selsky]

Adam Tauno Williams wrote:
> <http://www.horde.org/horde/docs/?f=PERFORMANCE.html>
> 
> Under "IMAP tuning" the link for Cyrus is
> <http://asg.web.cmu.edu/cyrus/download/imapd/install-perf.html> which is
> out of date.  The correct link [currently] should be
> <http://www.cyrusimap.org/docs/cyrus-imapd/2.4.2/install-perf.php>

Is there a URL that doesn't point at a specific Cyrus point-release?