list archives now refresh every 20 minutes

[Josip Rodin <joy@cibalia.gkvk.hr>]

Hi,

I've noticed no problems in the lists.d.o logs, each of the cronjob runs
took about two minutes, so I'm now changing the crontab to run the job every
twenty minutes.

I've also adjusted the savelog line to keep 72 copies of the logs, just in
case :)

-- 
     2. That which causes joy or happiness.