Revert "add debug logging for connection quality calculation" (#714)

This reverts commit 1c2c63e656.
The logging was initially added to help debug an issue with
connection quality showing lower than expected. The usefulness
of the logging has diminished and is noisy for browsers that
do not automatically filter console.debug, like Edge.

modules/connectivity/ConnectionQuality.js

         const resolution = Resolutions[resolutionName];
 
         let quality = 100;
-        let isSimulcastOn;
-        let millisSinceStart;
         let packetLoss;
-        let target;
 
         // TODO: take into account packet loss for received streams
 
             // Calculate a value based on the sending bitrate.
 
             // time since sending of video was enabled.
-            millisSinceStart = window.performance.now()
+            const millisSinceStart = window.performance.now()
                     - Math.max(this._timeVideoUnmuted, this._timeIceConnected);
 
             // Figure out if simulcast is in use
             const activeTPC = this._conference.getActivePeerConnection();
-
-            isSimulcastOn
+            const isSimulcastOn
                 = Boolean(activeTPC && activeTPC.isSimulcastOn());
 
             // expected sending bitrate in perfect conditions
-            target
+            let target
                 = getTarget(isSimulcastOn, resolution, millisSinceStart);
 
             target = Math.min(0.9 * target, MAX_TARGET_BITRATE);
                         + (diffSeconds * maxIncreasePerSecond));
         }
 
-        const connectionQuality = Math.min(100, quality);
-
-        console.debug('calculated connection quality', JSON.stringify({
-            connectionQuality,
-            isMuted,
-            isSimulcastOn,
-            lastUpdate: this._lastConnectionQualityUpdate,
-            millisSinceStart,
-            packetLoss,
-            resolution,
-            target,
-            upload: this._localStats.bitrate
-                && this._localStats.bitrate.upload
-        }));
-
-        return connectionQuality;
+        return Math.min(100, quality);
     }
 
     /**