ext/ogg/gstoggdemux.c: Fix EOS again. Needs to be done in a better way. We should not remove the pad if there is no n...

Original commit message from CVS:
* ext/ogg/gstoggdemux.c: (gst_ogg_demux_src_event),
(gst_ogg_demux_handle_event), (_find_chain_get_unknown_part),
(_find_streams_check), (gst_ogg_demux_push):
Fix EOS again. Needs to be done in a better way. We should not
remove the pad if there is no new chained stream.