Original commit message from CVS: * gst/matroska/matroska-mux.c: (gst_matroska_mux_request_new_pad), (gst_matroska_mux_release_pad), (gst_matroska_mux_write_data): Update the counter for the number of streams when pads are added or removed. This will make sure that a seek table is generated for files with just one audio stream.