* build-aux/hydra/demo-os.scm: Replace Emacs with Zile. Enable auto-login as "guest". This is the configuration used for the Guix 0.6 VM image.
* build-aux/hydra/demo-os.scm: New file. * Makefile.am (EXTRA_DIST): Add it. * build-aux/hydra/gnu-system.scm (qemu-jobs): New procedure. (hydra-jobs): Use it. * guix/scripts/system.scm (read-operating-system): Export.