OMG: Bumpy Gerrit update; have a KitKat

Updating Gerrit from 3.4 to 3.6 past 3.5 is causing some momentary Gerrit downtime, as lukegb notes:

[8:03:27 pm] <lukegb> gerrit 3.5.2 inited, copy-approvals is running
[8:08:36 pm] <Profpatsch> roger roger
[8:08:56 pm] <lukegb> still going
[8:09:29 pm] <lukegb> "NOTE: The execution of the copy-approvals SSH command (online) or the java -jar gerrit.war copy-approval site command (offline) may take a long time to complete due to the full scanning of all projects." oh
[8:12:14 pm] <tazjin> lukegb: is that what's going on now
[8:12:18 pm] <lukegb> yeah
[8:12:29 pm] <lukegb> have a kitkat

Everyone stay calm, this will be over soon inshallah.

Also noting a potential action item:

[8:12:30 pm] <tazjin> note to self for future: we should maybe have a maintenance page rather than a 502

1. tazjin updated the body of this issue at 2022-09-11T17·15+00

2. Luke noted that there was an issue with the copy-approvals script that is part of the Gerrit 3.5 update. Output here: https://gist.github.com/lukegb/38d337a8df5e1a19abf141a1f6317dd3

   tazjin at 2022-09-11T17·22+00

3. Things remain bumpy for now, please stay calm and note that there is a folded paper bag available in the back pocket of the seat in front of you.

   [8:33:09 pm] <lukegb> hrm, that's bad
   [8:33:52 pm] <lukegb> so gerrit can't read the plugin JARs for the builtin plugins out of the nix store because they're owned as root:root 600 for some reason
   [8:33:57 pm] <lukegb> (inside the nix store)
   [8:34:58 pm] <lukegb> I'm gonna kill gerrit-queue for a sec
   [8:37:01 pm] <tazjin> hmhm
   [8:37:15 pm] <lukegb> right, that was the reindexing
   [8:37:23 pm] <lukegb> I have a hunch, maybe I used the wrong java version when trying to copy-approvals
   [8:37:33 pm] <lukegb> I'm... gonna roll gerrit back and try again :P
   

   tazjin at 2022-09-11T17·38+00

4. lukegb defeated it, gerrit is now up to date

   tazjin at 2022-09-11T21·14+00

5. tazjin closed this issue at 2022-09-11T21·14+00