correctly handle selfsigned certificate

templates/apache-vhost.conf.j2

@@ -9,8 +9,10 @@
 
   SSLEngine on
   SSLCertificateFile "/etc/ssl/certs/nextcloud.cert.pem"
-  SSLCertificateChainFile "/etc/ssl/certs/nextcloud.chain.pem"
   SSLCertificateKeyFile "/etc/ssl/private/nextcloud.key.pem"
+  {% if not certificate_provider == "selfsigned" %}
+  SSLCertificateChainFile "/etc/ssl/certs/nextcloud.chain.pem"
+  {% endif %}
   {% if certificate_provider == "letsencrypt" %}
   Include /etc/letsencrypt/options-ssl-apache.conf
   {% endif %}