iron out.  TMCD/libsetup now has a plabconfig commands that parallels
the jailconfig command.  The Plab boot process has been added to
libsetup and a -p option has been added to vnodesetup to parallel the
-j option.  Parts of the code that were Jail-specific, but labeled
just as vnode stuff have been renamed.  $vnodedir in vnodesetup has
been removed, since it was redunant with libsetup's CONFDIR, and
CONFDIR is much more intelligent.