[Bucardo-general] turn off bucardo non-emergency email notifications?

[Jonathan Brinkman]

Hi there
I just installed an outgoing mail server (exim) on my bucardo server. 
Now I'm getting countless bucardo messages emailed to me.
How do I turn off email notifications - or at least the non-emergency ones?
Example message:
Cron <root at client-cloud-db-1> psql -X -q -d client_db -U bucardo -c "SELECT
bucardo_purge_delta('10 minutes'::interval);"