Re: subscriptionCheck failures on nightjar

I wrote:
> My animal dromedary just reproduced this failure, which we've previously
> only seen on nightjar.
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dromedary&dt=2019-06-26%2023%3A57%3A45

Twice:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dromedary&dt=2019-06-28%2006%3A50%3A41

Since this is a live (if old) system, not some weird qemu emulation,
we can no longer pretend that it might not be reachable in the field.
I've added an open item.

            regards, tom lane