remove unneeded assignments

lib/core/engine.js

@@ -32,7 +32,6 @@ class Engine {
   }
 
   init(_options) {
-    let self = this;
     let options = _options || {};
     this.events = options.events || this.events || new Events();
     this.logger = options.logger || new Logger({logLevel: options.logLevel || this.logLevel || 'debug', events: this.events, logFile: this.logFile});

lib/dashboard/dashboard.js

@@ -6,7 +6,6 @@ let Console = require('./console.js');
 
 class Dashboard {
   constructor(options) {
-    const self = this;
     this.logger = options.logger;
     this.events = options.events;
     this.plugins = options.plugins;