The default for the debian package is to use syslog and not a separate file. In this configuration, log rotations are done by the daily syslog cron job.
However, the administrator can certainly configure logging to a file instead, but if you consult the dovecot documentation/wiki on how to setup logging to a file (http://wiki.dovecot.org/Logging), then one would suppose the sample logrotate script provided on the same page would be sufficient. Unless there's objective, I propose closing this since it isn't an issue with the package. Joel -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org