Normally, logrotate is run as a daily cron job. It will not modify a log
multiple times in one day unless the criterion for that log is based on
the log's size and logrotate is being run multiple times each day, or
unless the -f or --force option is used.
This cleans up tmp and logrotates /var/log every 12 hours.
Note that this janitor is separate from the box janitor because they
run as different users.
Fixes#503