asfdemux: Send duration query upstream first
asfdemux: Send duration query upstream first

An upstream element (like mms or some dlna source) might be able to
answer the query. Try that first, else fallback to standard logic

GStreamer/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,Kurento/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,GStreamer/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,Kurento/gst-plugins-ugly,Kurento/gst-plugins-ugly,GStreamer/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,StreamUtils/gst-plugins-ugly