fix(AdaptiveQuality): prevent flickering on Unity 5.4.2

Whenever the render scale is changed the old frame is visible for some
time, looking like flickering when `AdaptiveQuality` is enabled. The
fix is to change the render scale in `LateUpdate` on Unity 5.4.2, too.

Author: Christopher - Marcel Böddecker

Assets/VRTK/Scripts/VRTK_AdaptiveQuality.cs

@@ -331,7 +331,7 @@ private void Update()
             timing.SaveCurrentFrameTiming();
         }
 
-#if UNITY_5_4_1 || UNITY_5_5_OR_NEWER
+#if UNITY_5_4_1 || UNITY_5_4_2 || UNITY_5_5_OR_NEWER
         private void LateUpdate()
         {
             UpdateRenderScale();
@@ -340,12 +340,12 @@ private void LateUpdate()
 
         private void OnCameraPreCull(Camera camera)
         {
-#if !(UNITY_5_4_1 || UNITY_5_5_OR_NEWER)
             if (camera.transform != VRTK_SDK_Bridge.GetHeadsetCamera())
             {
                 return;
             }
 
+#if !(UNITY_5_4_1 || UNITY_5_4_2 || UNITY_5_5_OR_NEWER)
             UpdateRenderScale();
 #endif
             UpdateMSAALevel();