Fix a "kibana" leftover in comments

src/config.sample.js

 /** @scratch /configuration/config.js/1
  * == Configuration
  * config.js is where you will find the core Grafana configuration. This file contains parameter that
- * must be set before kibana is run for the first time.
+ * must be set before Grafana is run for the first time.
  */
 define(['settings'],
 function (Settings) {