[Sage] Relative links breakage

[Harald Hanche-Olsen]

I am maintaining this atom feed:

  http://www.math.ntnu.no/conservation/atom/feed.xml

It uses relative links, as follows:

<feed xmlns="http://www.w3.org/2005/Atom"
      xml:base="http://www.math.ntnu.no/conservation/">
...
  <entry>
    <title>Convergence rate of ...</title>
    <link rel="alternate" type="text/html" href="2006/048.html"/>

It used to be that then the corresponding title field in sage would
point at

  http://www.math.ntnu.no/conservation/2006/048.html

thanks to the xml:base attribute at the top.  But now, all of a
sudden, it points to

  http://2006/048.html

instead, and that is rather useless I'm afraid.

Is this a new sage bug, or am I somehow coding my feed wrong?
I'd rather not have to code absolute URLs all over the place.

(The feed validates, apart from a single warning that I honestly don't
understand, but which does not seem relevant - as far as I can figure
out, it has to do with internal references (#name) in the document,
and I don't use those.)

- Harald