Merge remote-tracking branch 'remotes/ehabkost/tags/machine-pull-request' into staging

Machine Core queue, 2016-03-16

# gpg: Signature made Wed 16 Mar 2016 18:57:34 GMT using RSA key ID 984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"

* remotes/ehabkost/tags/machine-pull-request:
  module: Rename machine_init() to opts_init()
  machine: Use type_init() to register machine classes

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