Certbot excessive logging

[Saint Germain <saintger@gmail.com>]

With certbot 0.9.3-1~bpo8+2 on Debian Jessie (amd64), I got these
messages every 12 hours:
Feb 10 00:00:01 systemd[1]: Starting Certbot...
Feb 10 00:41:37 systemd[1]: Started Certbot.
Feb 10 12:00:01 systemd[1]: Starting Certbot...
Feb 10 12:29:38 systemd[1]: Started Certbot.

I reported the problem here:
https://github.com/certbot/certbot/issues/4210

But I've been told that the problem was in the systemd timer shipped in
the certbot package and that I should report it here.

Let me know if you need something else in order to turn these messages
off.

Best regards,