Merge pull request #304 from bgrozev/fix-a-warning

fix: Fixes a jshint or eslint warning.

modules/connectivity/ConnectionQuality.js

         let resolution = Resolutions[resolutionName];
 
         let quality = 100;
-        let packetLoss = undefined;
+        let packetLoss;
         // TODO: take into account packet loss for received streams
         if (this._localStats.packetLoss) {
             packetLoss = this._localStats.packetLoss.upload;