Fixes crash on "this.rtc" being "undefined" when JitsiLocalTrack.attach is called before it's added to the conference.

modules/RTC/JitsiLocalTrack.js

  */
 JitsiLocalTrack.prototype._setRTC = function (rtc) {
     this.rtc = rtc;
+    // We want to keep up with postponed events which should have been fired
+    // on "attach" call, but for local track we not always have the conference
+    // before attaching. However this may result in duplicated events if they
+    // have been triggered on "attach" already.
+    for(var i = 0; i < this.containers.length; i++)
+    {
+        this._maybeFireTrackAttached(this.containers[i]);
+    }
 };
 
 /**

modules/RTC/JitsiTrack.js

     }
 };
 
+/**
+ * Eventually will trigger RTCEvents.TRACK_ATTACHED event.
+ * @param container the video/audio container to which this stream is attached
+ *        and for which event will be fired.
+ * @private
+ */
+JitsiTrack.prototype._maybeFireTrackAttached = function (container) {
+    if (this.rtc && container) {
+        this.rtc.eventEmitter.emit(RTCEvents.TRACK_ATTACHED, this, container);
+    }
+};
+
 /**
  * Mutes the track.
  */
     }
     this.containers.push(container);
 
-    this.rtc.eventEmitter.emit(RTCEvents.TRACK_ATTACHED, this, container);
+    this._maybeFireTrackAttached(container);
 
     return container;
-}
+};
 
 /**
  * Removes the track from the passed HTML container.