9999 loader: Consolidate three copies of ZFS commands into a central location.
Review Request #1292 - Created Nov. 21, 2018 and submitted
FreeBSD update: https://svnweb.freebsd.org/base?view=revision&revision=329725 There's no reason to have multiple copies of lszfs and reloadbe. Consolidate them into one location. Also ldi_get_size is the same everywhere (except sparc64). Make it the same everywhere as the common definition is more general and will work on spar64.