Koa.2a has been tagged

It turns out that yesterday’s koa.2 included a showstopping bug in the native installation. It only affects a single-server installation, but because multiple people have been affected, we decided to put out a new tag, open-release/koa.2a, that addresses the problem.

This is the only change from koa.2:

---- ./configuration ----
87199d5fd 2021-01-18 syedimranhassan: fix: mysql5.7 installation failures (from pull #6248)