[Mailman] mailman signup broken (http vs https issue)

[Dan S]

Hi -

I am unable to sign up to OSM mailing lists, and I think it's because
of a HTTP vs HTTPS redirect issue.

* I go to https://lists.openstreetmap.org/
*I find a nice list, I fill in some details
* I get an email confirmation, I click the link within, then I click
"confirm subscription" in the web form

Then the problem appears: (a) my browser warns me about submitting a
form from HTTPS->HTTP being insecure; (b) the next page is not
"welcome to mailing list" but "Please enter the confirmation string
(i.e. cookie) that you received in your email message".

I suspect the problem is that the <form> is targeted at "http://..."
and then something on the server redirects me to "https://..." in such
a way as to forget the post data. (The same thing happens if I try to
type in the confirmation code manually, since that's also a
"http://..." form)

Thanks
Dan