[core] Unused configuration option

Author: iartem

api/config.sample.js

@@ -151,7 +151,4 @@ var countlyConfig = {
     */
 };
 
-// Set your host IP or domain to be used in the emails sent
-// countlyConfig.host = "YOUR_IP_OR_DOMAIN";
-
 module.exports = require('./configextender')('API', countlyConfig, process.env);