[HVM-537] Add cpu_type=host for Ubuntu zvol dataset.
[HVM-537] Add cpu_type=host for Ubuntu zvol dataset.

kaizengarden/sdc-headnode,joyent/sdc-headnode,kaizengarden/sdc-headnode,kaizengarden/sdc-headnode,numericillustration/sdc-headnode,joyent/sdc-headnode,joyent/sdc-headnode,kaizengarden/sdc-headnode,joyent/sdc-headnode,numericillustration/sdc-headnode,numericillustration/sdc-headnode