broth needs a .list switch to replace old -o

[Aymeric Mansoux]

Starting with lh 2.0a, the packages list's behaviour is slightly different:

16:41 < panthera> a) every match to config/chroot_local-packageslists/*.list should be used automatically
16:41 < panthera> b) if --packages-lists is used, the list should be looked up in this order:
16:41 < panthera> /usr/share/live-helper/lists
16:41 < panthera> config/chroot_local-packageslists
16:42 < panthera> (both times without the .list suffix)

but b) is broken now, so we need a script that will switch .list profiles. As a temp fix the current broth has puredyne-CD as default .list, even though there won't be any errors it will be always the CD built no matter which -o is given.