mainapp: Add @Override annotation to onCreate()

src/main/java/com/owncloud/android/MainApp.java

@@ -110,6 +110,7 @@ public class MainApp extends MultiDexApplication {
     private boolean mBound;
 
     @SuppressFBWarnings("ST")
+    @Override
     public void onCreate() {
         super.onCreate();
         JobManager.create(this).addJobCreator(new NCJobCreator());