[Dovecot] Reduce logging auth-worker

Hello Timo

We would like to reduce the logging by increasing severity, we don't use syslog since we use

log_path = /var/log/dovecot/pop3.log

Is there a way auth-worker can be made to log warn|error instead of info?

Constantly 1/5th of the log file is filled with auth-work info connecting to mysql socket, which we do not need to see unless, well, we need to see it either via debug, or if there is a problem, I know this can be done from syslog, but we prefer not to use syslog, and the wiki does not indicate it can be done?

Niki