Set a command name rather than creating a pseudo-bitmask that requires
each case to be updated each time a command is added.

The archive subcommand (-A) creates a tar file containing the contents
of a jail and it's metadata.  The create subcommand (-c) gains a new
method to create a new jail from an archive, restoring its metadata.
This can be used to save a copy of a jail before updates or to transfer
a jail to another machine.