HEAD-1608 add support for reflashing using usb image
HEAD-1608 add support for reflashing using usb image

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