asfdemux: Don't error out on non-critical flow returns
asfdemux: Don't error out on non-critical flow returns

Only error out when downstream returns:
* NOT_SUPPORTED
* ERROR
* NOT_NEGOTIATED
* NOT_LINKED

If we got _UNEXPECTED, we push an EOS downstream (since maybe only one
of the streams had gone EOS) and then stop the task silently.

In the case of WRONG_STATE we just need to stop silently

https://bugzilla.gnome.org/show_bug.cgi?id=600412

collects/gst-plugins-ugly,alessandrod/gst-plugins-ugly,jahrome/gst-plugins-ugly,sebras/gst-plugins-ugly,GStreamer/gst-plugins-ugly,sebras/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,Distrotech/gst-plugins-ugly,collects/gst-plugins-ugly,alessandrod/gst-plugins-ugly,jar1karp/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,krieger-od/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-ugly,cablelabs/gst-plugins-ugly,fluendo/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,cablelabs/gst-plugins-ugly,ahmedammar/platform_external_gst_plugins_ugly,jpakkane/gstreamer-plugins-ugly,ahmedammar/platform_external_gst_plugins_ugly,StreamUtils/gst-plugins-ugly,Distrotech/gst-plugins-ugly,knuesel/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,krieger-od/gst-plugins-ugly,Distrotech/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-ugly,ahmedammar/platform_external_gst_plugins_ugly,ylatuya/gst-plugins-ugly,Distrotech/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,GStreamer/gst-plugins-ugly,jahrome/gst-plugins-ugly,knuesel/gst-plugins-ugly,jar1karp/gst-plugins-ugly,matsu/gst-plugins-ugly,surround-io/gst-plugins-ugly,matsu/gst-plugins-ugly,Lachann/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,collects/gst-plugins-ugly,knuesel/gst-plugins-ugly,Distrotech/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,jahrome/gst-plugins-ugly,jar1karp/gst-plugins-ugly,sebras/gst-plugins-ugly,krieger-od/gst-plugins-ugly,matsu/gst-plugins-ugly,fluendo/gst-plugins-ugly,krieger-od/gst-plugins-ugly,Lachann/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,surround-io/gst-plugins-ugly,Kurento/gst-plugins-ugly,Kurento/gst-plugins-ugly,surround-io/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-ugly,ylatuya/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,Lachann/gst-plugins-ugly,cablelabs/gst-plugins-ugly,alessandrod/gst-plugins-ugly,GStreamer/gst-plugins-ugly,Kurento/gst-plugins-ugly,ylatuya/gst-plugins-ugly,matsu/gst-plugins-ugly,collects/gst-plugins-ugly,fluendo/gst-plugins-ugly