The Virtualhost order changed, but because it had to. I'm aware the "default" is now mrtg.livejournal.com.
Before we had:
1) livejournal.com www.livejournal.com
2) mrtg.livejournal.com
3) *.livejournal.com
When I did the rewrite stuff, it changed to:
1) livejournal.com *.livejournal.com
2) mrtg.livejournal.com
But that broke mrtg, because vhost #1 caught mrtg.livejournal.com with that *.livejournal.com alias
So I moved mrtg.livejournal.com above.
Screw broken HTTP/1.0 clients. Host: headers have been in use for years before HTTP/1.1, even. Netscape 3.0 sent them, IIRC, and maybe even 2.0.