machine: Replace underscores in machine's property names

Replaced '_' with '-' to comply with QOM guidelines.
Made the conversion from command line to QMP in vl.c.

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Merge remote-tracking branch 'remotes/afaerber/tags/qom-devices-for-2.1' into staging

QOM and device refactorings

* Machine: Property name fixups for 2.1 ABI

# gpg: Signature made Mon 21 Jul 2014 18:00:23 BST using RSA key ID 3E7E013F
# gpg: Good signature from "Andreas Färber <afaerber@suse.de>"
# gpg:                 aka "Andreas Färber <afaerber@suse.com>"

* remotes/afaerber/tags/qom-devices-for-2.1:
  machine: Replace underscores in machine's property names

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