Buildbot infrastructure upgrade

[Hannu Nyman]

Petr Štetiar kirjoitti 18.3.2021 klo 12.12:
>
> I'm still not that happy with the round-robin scheduler[1], but it's better 
> then the previous state, so I'm going to deploy it soon to all masters.
>
> ...
>
> 1. https://github.com/buildbot/buildbot/issues/4592#issuecomment-801163587
>
> Cheers,
>
> Petr


I noticed that the master packages buildbot just started a new 
mips64_octeonplus build, but only removed one of the pending build requests 
(9 hours old) from the queue. The newer buildrequest 1344 that is 41 minutes 
old, is still in the queue.

https://buildbot.openwrt.org/master/packages/#/builders/4
https://buildbot.openwrt.org/master/packages/#/pendingbuildrequests


The same seems to have happened to i386_pentium-mmx (while I was writing this).

So, a started build for a target does not always clear the build request 
queue, as intended.