Silence letsencrypt cron output unless there is an error

roles/common/files/etc_cron-daily_letsencrypt-renew

@@ -3,6 +3,6 @@ set -o errexit
 # Renew all live certificates with LetsEncrypt.  This needs to run at least
 # once every three months, but recommended frequency is once a day.
 
-/root/letsencrypt/letsencrypt-auto renew -c /etc/letsencrypt/cli.conf \
+/root/letsencrypt/letsencrypt-auto renew -q -c /etc/letsencrypt/cli.conf \
 --pre-hook="find /etc/letsencrypt/prerenew/ -maxdepth 1 -type f -executable -exec {} \;" \
 --post-hook="find /etc/letsencrypt/postrenew/ -maxdepth 1 -type f -executable -exec {} \;"