Use a default

templates/etc-apache2-sites-available-vhost

@@ -18,7 +18,7 @@
   SetEnvIf X-Forwarded-For "^.*\..*\..*\..*" forwarded
   CustomLog ${APACHE_LOG_DIR}/access.log combined env=!forwarded
   CustomLog ${APACHE_LOG_DIR}/access.log proxy env=forwarded
-{% for alias in item.aliases %}
+{% for alias in item.aliases|default([]) %}
 
     Alias /sysadmin/ "/var/www/{{alias.path}}/"
     <Directory "/var/www/{{alias.path}}/">