impossible to clone from http

[Thomas Bouffon <thomas bouffon gmail com>]

Hi, 
I'm behind a proxy and can't clone via git://.  A few weeks ago, I managed to build gnome-shell, replacing the git repos by http.
Today I tried to build everything again, but I cannot clone anything anymore :  I get : 
 $ bash gnome-shell-build-setup.sh 
Checking out jhbuild into /home/tbouffon/Source/jhbuild ... fatal: http://git.gnome.org/jhbuild/info/refs not found: did you run git update-server-info on the server?

But I can wget refs.
Has anyone any idea why I get this ?
Thanks, Thomas