ZFS root mount regression

[Garrett Wollman]

<<On Sat, 20 Jul 2019 17:41:39 +0700, Eugene Grosbein <eugen at grosbein.net> said:

> Both 11.3-RELEASE announcement and Release Notes mention this:

>> The ZFS filesystem has been updated to implement parallel mounting.

> I strongly suggest reading Release documentation in case of troubles
> after upgrade, at least. Or better, read *before* updating.

Two servers breaking out of thirty-five upgraded is not the sort of
thing that you'd expect to be implied by such a statement, especially
when there's only one filesystem being mounted at the relevant time.

-GAWollman