Fixes issues after review

JitsiConferenceEventManager.js

 
                         conference.eventEmitter.emit(
                             JitsiConferenceEvents.TRACK_REMOVED, track);
-                        
+
                         if(conference.transcriber){
-                            conference.transcriber.removeTrack(track);    
+                            conference.transcriber.removeTrack(track);
                         }
-                        
+
                         return;
                     }
                 }
     });
 
     conference.statistics.addByteSentStatsListener(function (stats) {
-        var tracks = conference.getLocalTracks();
         conference.getLocalTracks().forEach(function (track) {
             var ssrc = track.getSSRC();
             if(!track.isAudioTrack() || !ssrc || !stats.hasOwnProperty(ssrc))

modules/RTC/JitsiLocalTrack.js

     // enumerateDevices() list.
     this._trackEnded = false;
 
+    /**
+     * The value of bytes sent received from the statistics module.
+     */
     this._bytesSent = null;
 
+    /**
+     * Used only for detection of audio problems. We want to check only once
+     * whether the track is sending bytes ot not. This flag is set to false
+     * after the check.
+     */
     this._testByteSent = true;
 
     // Currently there is no way to determine with what device track was