Merge pull request #111 from jitsi/callstats_error

Fix JS error returned by callstats when no error is passed to be reported

modules/statistics/CallStats.js

@@ -302,6 +302,10 @@ function(overallFeedback, detailedFeedback) {
  * @private
  */
 CallStats._reportError = function (type, e, pc) {
+    if(!e) {
+        logger.warn("No error is passed!");
+        e = new Error("Unknown error");
+    }
     if (callStats) {
         callStats.reportError(pc, this.confID, type, e);
     } else {