Patch applied to the repository. For future reference, just attach the output of the diff as the patch file. The attachment you provided is an html file, not a patch file.
[dovecot] Fixed typos, by Vladimir Lomov
I think I found a version of your patch, which it's been incorporated in the repository.
[dovecot] Support for dovecot version 2.4, by Vladimir Lomov.
That appears to be the clamav service. Does that mean that the clam-update service did not show any output? Have you set $Clam_Update_Detail=1 in /etc/logwatch/conf/services/clam-update? Otherwise, what is the value of Detail in /etc/logwatch/conf/logwatch.conf? Besides running logwatch --service clam-update, if you want to see what the cron/anacron job outputs, you can run logwatch --output mail. That is the command run by default every day. You can re-run it at any time (not having to wait overnight),...
The link is not valid. Can you re-post the patch as an attachment? That's for the 2.4 changes; the correction to the spacing was already committed.
I've updated the clam-update script to use a service-specific variable clam_update_detail, which can be set in conf/services/clam-update.conf. The script also accepts the --debug option (logwatch --service clam-update --debug 1 --detail 1, for example) to show how the detail level is set. It appears that when setting the detail to 1 it shows the output you expect.
Fix small white space issue in scripts/service/dovecot