Instructions have been updated in here:
https://wiki.mozilla.org/Mobile/Build/cs2007q3
and wrt to build machines in here:
https://wiki.mozilla.org/ReferencePlatforms/Linux-CentOS-5.0#Post-puppet_packages
Thanks to mfinkle for having written such detailed description when
filing the bug.
For full details read:
https://bugzilla.mozilla.org/show_bug.cgi?id=529462