asfdepay: fix padding correction
asfdepay: fix padding correction

Fix padding correction. gst_buffer_copy_into() appends the memory to the already
existing memory in the target buffer..

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=680536

cablelabs/gst-plugins-ugly,krieger-od/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,StreamUtils/gst-plugins-ugly,jar1karp/gst-plugins-ugly,cablelabs/gst-plugins-ugly,Distrotech/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,surround-io/gst-plugins-ugly,GStreamer/gst-plugins-ugly,Distrotech/gst-plugins-ugly,Distrotech/gst-plugins-ugly,collects/gst-plugins-ugly,Lachann/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,GStreamer/gst-plugins-ugly,Kurento/gst-plugins-ugly,Kurento/gst-plugins-ugly,collects/gst-plugins-ugly,surround-io/gst-plugins-ugly,krieger-od/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,collects/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,jpakkane/gstreamer-plugins-ugly,sebras/gst-plugins-ugly,krieger-od/gst-plugins-ugly,cablelabs/gst-plugins-ugly,sebras/gst-plugins-ugly,sebras/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,Lachann/gst-plugins-ugly,jar1karp/gst-plugins-ugly,surround-io/gst-plugins-ugly,Kurento/gst-plugins-ugly,jar1karp/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,GStreamer/gst-plugins-ugly,Distrotech/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,StreamUtils/gst-plugins-ugly,Lachann/gst-plugins-ugly,krieger-od/gst-plugins-ugly,Distrotech/gst-plugins-ugly,collects/gst-plugins-ugly