Fix onPause vs onStop

Revert convivaAnalyticsIntegration = null

ConvivaExampleApp/src/main/java/com/bitmovin/analytics/convivaanalyticsexample/MainActivity.java

@@ -147,7 +147,7 @@ protected void onResume() {
     protected void onPause() {
         super.onPause();
         if (bitmovinPlayerView != null) {
-            bitmovinPlayerView.onStop();
+            bitmovinPlayerView.onPause();
         }
     }
 
@@ -167,6 +167,7 @@ protected void onDestroy() {
         }
         if (convivaAnalyticsIntegration != null) {
             convivaAnalyticsIntegration.release();
+            convivaAnalyticsIntegration = null;
         }
     }