web: start with clean config.js

web/rootfs/etc/cont-init.d/10-config

@@ -75,7 +75,7 @@ tpl /defaults/ssl.conf > /config/nginx/ssl.conf
 
 tpl /defaults/default > /config/nginx/site-confs/default
 
-tpl /defaults/system-config.js >> /config/config.js
+tpl /defaults/system-config.js > /config/config.js
 tpl /defaults/settings-config.js >> /config/config.js
 if [[ -f /config/custom-config.js ]]; then
     cat /config/custom-config.js >> /config/config.js