Call super.onCreate() in Application.

Just in case Application#onCreate() does something, though as of now it
does nothing for real.

app/src/main/java/com/google/android/sambadocumentsprovider/SambaProviderApplication.java

@@ -49,6 +49,8 @@ public class SambaProviderApplication extends Application {
 
   @Override
   public void onCreate() {
+    super.onCreate();
+
     final ConnectivityManager manager =
         (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
     manager.registerNetworkCallback(