only handle setNextSource iff abouttofinish is active
only handle setNextSource iff abouttofinish is active

if we go to stopped after phonon handed us a source it will simply set
it as regular source, so we do not need any special handling for the
next source call at all

shadeslayer/phonon-gstreamer,shadeslayer/phonon-gstreamer,KDE/phonon-gstreamer,KDE/phonon-gstreamer,shadeslayer/phonon-gstreamer