Android: Call release() in AndroidMediaMetadataRetriever's destructor.

This should be the default when the wrapper is destroyed.

Note: It's not possible to re-use the instance after release() is
called.

Change-Id: I761cac05ed2c2cda49573c69c6803b136892c528
Reviewed-by: Yoann Lopes <yoann.lopes@theqtcompany.com>

src/plugins/android/src/mediaplayer/qandroidmetadatareadercontrol.cpp

@@ -230,8 +230,6 @@ void QAndroidMetaDataReaderControl::extractMetadata(QAndroidMetaDataReaderContro
         string = retriever.extractMetadata(AndroidMediaMetadataRetriever::Year);
         if (!string.isNull())
             metadata.insert(QMediaMetaData::Year, string.toInt());
-
-        retriever.release();
     }
 
     const QMutexLocker lock(g_metaDataReadersMtx);

src/plugins/android/src/wrappers/jni/androidmediametadataretriever.cpp

@@ -60,6 +60,7 @@ AndroidMediaMetadataRetriever::AndroidMediaMetadataRetriever()
 
 AndroidMediaMetadataRetriever::~AndroidMediaMetadataRetriever()
 {
+    release();
 }
 
 QString AndroidMediaMetadataRetriever::extractMetadata(MetadataKey key)

src/plugins/android/src/wrappers/jni/androidmediametadataretriever.h

@@ -71,10 +71,10 @@ public:
     ~AndroidMediaMetadataRetriever();
 
     QString extractMetadata(MetadataKey key);
-    void release();
     bool setDataSource(const QUrl &url);
 
 private:
+    void release();
     QJNIObjectPrivate m_metadataRetriever;
 };