ext/ogg/gstoggdemux.c: Return query failure when we don't know the length of an ogg stream insteda of returning TRUE ...

Original commit message from CVS:
* ext/ogg/gstoggdemux.c: (gst_ogg_demux_src_query),
(gst_ogg_demux_push):
Return query failure when we don't know the length of
an ogg stream insteda of returning TRUE with a bogus value.