[sugar] xulrunner beta5 in sugar-jhbuild

[Simon Schampijer]

Hi,

I have updated sugar-jhbuild to use the xulrunner beta 5 sources 
http://developer.mozilla.org/devnews/index.php/2008/04/02/firefox-3-beta-5-now-available-for-download/

It passed the buildbot test as well: 
http://iorich.caltech.edu:8014/A/builds/203

Enjoy,
    Simon