hydra: Remove 'qemu-image' job.

As per the discussion at
<https://lists.gnu.org/archive/html/guix-devel/2016-12/msg01098.html>.

* build-aux/hydra/gnu-system.scm (demo-os): Remove.
(qemu-jobs): Remove 'qemu-image' job.
* build-aux/hydra/demo-os.scm: Remove.

build-aux/hydra/demo-os.scm

@@ -1,84 +0,0 @@
-;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2015 Ludovic Courtès <ludo@gnu.org>
-;;;
-;;; This file is part of GNU Guix.
-;;;
-;;; GNU Guix is free software; you can redistribute it and/or modify it
-;;; under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation; either version 3 of the License, or (at
-;;; your option) any later version.
-;;;
-;;; GNU Guix is distributed in the hope that it will be useful, but
-;;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-;;; GNU General Public License for more details.
-;;;
-;;; You should have received a copy of the GNU General Public License
-;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
-
-
-;;;
-;;; This file defines an operating system configuration for the demo virtual
-;;; machine images that we build.
-;;;
-
-(use-modules (gnu))
-(use-service-modules desktop xorg networking avahi dbus)
-(use-package-modules linux xorg tor avahi)
-
-(operating-system
- (host-name "gnu")
- (timezone "Europe/Paris")
- (locale "en_US.utf8")
-
- (bootloader (grub-configuration
-              (device "/dev/sda")))
- (file-systems
-  ;; We provide a dummy file system for /, but that's OK because the VM build
-  ;; code will automatically declare the / file system for us.
-  (cons* (file-system
-           (mount-point "/")
-           (device "dummy")
-           (type "dummy"))
-         ;; %fuse-control-file-system   ; needs fuse.ko
-         ;; %binary-format-file-system  ; needs binfmt.ko
-         %base-file-systems))
-
- (users (list (user-account
-               (name "guest")
-               (group "users")
-               (supplementary-groups '("wheel"))  ; allow use of sudo
-               (password "")
-               (comment "Guest of GNU")
-               (home-directory "/home/guest"))))
-
- (issue "
-This is an alpha preview of the GNU system.  Welcome.
-
-This image features the GNU Guix package manager, which was used to
-build it (http://www.gnu.org/software/guix/).  The init system is
-the GNU Shepherd (http://www.gnu.org/software/shepherd/).
-
-You can log in as 'guest' or 'root' with no password.
-")
-
- (services (cons* (slim-service #:auto-login? #t
-                                #:default-user "guest")
-
-                  ;; QEMU networking settings.
-                  (static-networking-service "eth0" "10.0.2.10"
-                                             #:name-servers '("10.0.2.3")
-                                             #:gateway "10.0.2.2")
-
-                  (avahi-service)
-                  (dbus-service)
-                  (tor-service)
-
-                  %base-services))
- (pam-services
-  ;; Explicitly allow for empty passwords.
-  (base-pam-services #:allow-empty-passwords? #t))
-
- (packages (cons* strace
-                  tor torsocks
-                  xterm avahi %base-packages)))

build-aux/hydra/gnu-system.scm

@@ -125,12 +125,6 @@ SYSTEM."
     "arm-linux-gnueabihf"
     "i686-w64-mingw32"))
 
-(define (demo-os)
-  "Return the \"demo\" 'operating-system' structure."
-  (let* ((dir  (dirname (assoc-ref (current-source-location) 'filename)))
-         (file (string-append dir "/demo-os.scm")))
-    (read-operating-system file)))
-
 (define %guixsd-supported-systems
   '("x86_64-linux" "i686-linux"))
 
@@ -156,14 +150,7 @@ system.")
     (expt 2 20))
 
   (if (member system %guixsd-supported-systems)
-      (list (->job 'qemu-image
+      (list (->job 'usb-image
-                   (run-with-store store
-                     (mbegin %store-monad
-                       (set-guile-for-build (default-guile))
-                       (system-qemu-image (demo-os)
-                                          #:disk-image-size
-                                          (* 1400 MiB))))) ; 1.4 GiB
-            (->job 'usb-image
                    (run-with-store store
                      (mbegin %store-monad
                        (set-guile-for-build (default-guile))