fix unregistered messagReceiver

mobile/src/main/java/cn/garymb/ygomobile/ui/home/MainActivity.java

@@ -162,7 +162,7 @@ public class MainActivity extends HomeActivity {
     protected void onDestroy() {
         YGOStarter.onDestroy(this);
         super.onDestroy();
-        if (mResCheckTask != null)
+        if (mResCheckTask.mReceiver != null)
             mResCheckTask.unregisterMReceiver();
     }
 

mobile/src/main/java/cn/garymb/ygomobile/ui/home/ResCheckTask.java

@@ -277,7 +277,6 @@ public class ResCheckTask extends AsyncTask<Void, Integer, Integer> {
             FileUtils.copyDir(textures, mSettings.getCoreSkinPath());
             FileUtils.copyDir(pics, mSettings.getCardImagePath());
 
-
             han.sendEmptyMessage(0);
 
             loadData();