Description of problem:
If you have a list with a private archive and you follow the mail header present
in the list mails
List-Archive: <http://host0.dyn.jankratochvil.net/mailman/private/vmezihori1>
the URL does not work.

Version-Release number of selected component (if applicable):
mailman-2.1.9-10.fc9.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. Create a mailing list.
2. Set its archive to private (`archive_private').
3. Try to browser the List-Archive URL.
4. Click the `[ Thread ]' button.

Actual results:
On URL:
http://host0.dyn.jankratochvil.net/mailman/private/2008-May/thread.html
Message: No such list 2008-may

Expected results:
On URL:
http://host0.dyn.jankratochvil.net/mailman/private/vmezihori1/2008-May/thread.html
The right content.

Additional info:
The problem is on the public archive it is a regular directory where httpd
automatically gives a redirect with a trailing slash.
The private lists are handled by CGI /usr/lib/mailman/cgi-bin/private which does
not give such redirect.
The link from the listinfo page works fine as it has the trailing slash.
Solution:
(1) The List-Archive mail header should also have the trailing slash.
OR
(2) /usr/lib/mailman/cgi-bin/private should return the redirect.