Always show the error code in Demo app when error happens

If a successful playback was done before an error occured
the error code was not shown in the Demo app. Fixed this.

demoApplication/src/main/java/com/sonymobile/android/media/testmediaplayer/MainActivity.java

@@ -928,6 +928,7 @@ public void setMediaBrowserState(ListAdapter adapter, String path) {
     @Override
     public boolean onError(MediaPlayer mp, int what, int extra) {
         mSubtitleView.setText("Error " + errorCodeToString(what));
+        mSubtitleView.setLayoutParams(mSubtitleLayoutBottom);
         mIsBuffering = false;
         toggleLoading(false);
         mIsPrepared = false;