playbin3: Collect appropriate stream-type when doing stream selection

https://bugzilla.gnome.org/show_bug.cgi?id=796193
diff --git a/gst/playback/gstplaybin3.c b/gst/playback/gstplaybin3.c
index edb77bd..027766b 100644
--- a/gst/playback/gstplaybin3.c
+++ b/gst/playback/gstplaybin3.c
@@ -2360,7 +2360,7 @@
           playbin->audio_stream_combiner != NULL);
       nb_audio++;
     } else if (stream_type & GST_STREAM_TYPE_VIDEO) {
-      pb_stream_type = PLAYBIN_STREAM_AUDIO;
+      pb_stream_type = PLAYBIN_STREAM_VIDEO;
       select_this =
           (nb_video == playbin->current_video ||
           (playbin->current_video == -1 && nb_video == 0) ||