truenas/py-libzfs is dead

After maintaining py-libzfs for many years, the folks at ixSystems are
shutting it down.  They're putting their efforts into a new library
instead, but the new library isn't intended to be portable; it's for
TrueNAS Scale only.  But I for one still use py-libzfs.  So js@ and I
are preparing a fork.  I don't know for how much longer we'll continue
to use it.  We might just rewrite all of our code instead.  But for at
least a little while, we'll ensure that py-libzfs continues to work on
FreeBSD.  My fork isn't quite ready, but it will be soon, and then
I'll update filesystems/py-libzfs .

Old home: https://github.com/truenas/py-libzfs
New home: https://github.com/asomers/py-libzfs

So long ixSystems, and thanks for all the libs

-Alan