Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20150702-v3' into staging

Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20150702-v3' into staging

Several s390x patches including:
- missing virtio-1 related code for virtio-ccw
- bugfixes in ipl device, gdb, virtio-ccw
- bugfix in s390-ccw bios + rebuild
- introduce versioned machines for s390-ccw-virtio

# gpg: Signature made Thu Jul  2 15:05:34 2015 BST using RSA key ID C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"

* remotes/cohuck/tags/s390x-20150702-v3:
  s390x/migration: Introduce 2.4 machine
  s390x/gdb: synchronize cpu state after modifying acrs
  s390x/ipl: Fix boot if no bootindex was specified
  virtio-ccw: migrate ->revision
  s390x/virtio-ccw: support virtio-1 set_vq format
  s390x/virtio-ccw: add virtio set-revision call
  s390x/css: Add a callback for when subchannel gets disabled
  s390-ccw.img: update
  s390-ccw.img: Consume service interrupts
  css: mss/mcss-e vs. migration
  virtio-ccw: complete handling of guest-initiated resets

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>