Add missing autotest.

The QSoundEffect test was missing in the initial modularization.

Change-Id: I92ba5290b28a4af3a1d4bd8f8a036e14a75cf8d1
Reviewed-on: http://codereview.qt.nokia.com/1400
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Ling Hu <ling.hu@nokia.com>
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>

tests/auto/multimedia.pro

@@ -40,7 +40,7 @@ contains (QT_CONFIG, declarative) {
   # All the declarative tests depend on private interfaces
   contains (QT_CONFIG, private_tests) {
     SUBDIRS += \
-#    qsoundeffect \
+    qsoundeffect \
     qdeclarativeaudio \
     qdeclarativevideo
   }