With pull request #1476 (not yet merged) comes a verbose warning
if /usr/bin/net doesn't exist or isn't executable. Just create
a dummy...
* If user haven't specified pool, but bootfs then use the first part
  of the bootfs path as pool name.
* Add support for booting of a ZFS snapshot.
  Do this by cloning the snapshot into a dataset. If this dataset already
  exists, destroy it.
  !! WARNING: Untested !!