Upgrade to mailman 2.0beta5

[Owen Taylor <otaylor redhat com>]

I've just upgraded mail.gnome.org to mailman 2.0beta5.

The two main improvements that I hope this will provide are:

 - Improved handling of bounces. (Less bounces in your mailboxes!)
 - Less propensity to lose password cookies

There may also be other assorted bugs that it fixes. Let me
know if you see any problems. 

Thanks,
                                        Owen

[
 I've also created the mailing list listowners@gnome.org, that
 is supposed to include all list owners, though I may have
 missed a few. If you create any new lists, you should add
 the owners to this list. It should be _really_ low traffic.
]