Currently, the module fail with a error saying that --acme-dir is mandatory.
Looking at the commandline:
/usr/sbin/acme-tiny --chain --account-key /srv/letsencrypt/acme_key/acme.key
--csr /srv/letsencrypt/nginx_certs/www.example.org.csr--acme-dir /srv/letsencrypt/webroot",
We can see that the space before --acme-dir is missing.
