[Assets] Fix Nextcloud site

data/assets/nextcloud/nextcloud.conf

@@ -10,7 +10,6 @@ server {
   charset utf-8;
   override_charset on;
 
-  ssl on;
   ssl_certificate /etc/ssl/mail/cert.pem;
   ssl_certificate_key /etc/ssl/mail/key.pem;
   ssl_protocols TLSv1.2;