Fix issue with playing an audio file on android smallbasic#231

Author: chrisws

src/platform/android/app/src/main/java/net/sourceforge/smallbasic/MainActivity.java

@@ -462,12 +462,6 @@ public boolean onError(MediaPlayer mp, int what, int extra) {
                   return true;
                 }
               });
-              _mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
-                @Override
-                public void onCompletion(MediaPlayer mp) {
-                  releaseMediaPlayer();
-                }
-              });
             } else {
               _mediaPlayer.reset();
             }