HEAD-1229 upgrade: add verification-only option
HEAD-1229 upgrade: add verification-only option

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