message: Stop receiving MediaStream events when subscriber is closed
diff: @@ -14,8 +14,9 @@ class Subscriber extends NodeClass {
  this.connection.mediaConfiguration = options.mediaConfiguration;
  this.connection.addMediaStream(this.erizoStreamId, options, false);
  this._connectionListener = this._emitStatusEvent.bind(this);
  + this._mediaStreamListener = this._onMediaStreamEvent.bind(this);
  connection.on('status_event', this._connectionListener);
  - connection.on('media_stream_event', this._onMediaStreamEvent.bind(this));
  + connection.on('media_stream_event', this._mediaStreamListener);
  this.mediaStream = connection.getMediaStream(this.erizoStreamId);
  this.publisher = publisher;
  this.ready = false;
  @@ -126,6 +127,7 @@ class Subscriber extends NodeClass {
  if (this.connection) {
  this.connection.removeMediaStream(this.mediaStream.id);
  this.connection.removeListener('status_event', this._connectionListener);
  + this.connection.removeListener('media_stream_event', this._mediaStreamListener);
  }
  if (this.mediaStream && this.mediaStream.monitorInterval) {
  clearInterval(this.mediaStream.monitorInterval);
  