Set volume only if volume was explicitly set.

Change-Id: I0d5abab0ffbf61a74c59ce240fd39e756479026b
Done-with: Juho Hämäläinen <juho.hamalainen@tieto.com>
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>

src/multimedia/audio/qsoundeffect_pulse_p.h

@@ -181,6 +181,10 @@ private:
     bool m_resourcesAvailable;
 
     QMediaPlayerResourceSetInterface *m_resources;
+
+#if defined(Q_WS_MAEMO_6) || defined(NEMO_AUDIO)
+    bool m_customVolume;
+#endif
 };
 
 QT_END_NAMESPACE