FreeBSD 13.0 released

FYI, it went wrong even without my running zpool upgrade. I just ran zpool upgrade because it felt like it was probably time, and it never suggested I run anything else. It completed silently. (I reinstalled the bootloader anyway, just in case.)

This was less painful than it sounds because it's all in a backed-up QEMU VM and after the first failure I restored it from backup and started experimenting using poor-man's-snapshots (i.e. cp --reflink of the image): the only painful part was that testing it involved a complete portupgrade -afR, which takes *forever*.

(I find using cp --reflink often preferable to real QEMU snapshots if I might want to decide to preserve a snapshot at any time without a shutdown *and* I don't know if I'll want to preserve the image I'm changing later *and* I don't want my experiments to bloat the image -- usually, QEMU in-image snapshots give the first of these properties and disk images with backing stores give the other two, but cp --reflink gives all at once :) ).