gst/realmedia/rmdemux.c: When operating in pull mode, post an error message on the...

gst/realmedia/rmdemux.c: When operating in pull mode, post an error message on the bus when all source pads are unlin...

Original commit message from CVS:
* gst/realmedia/rmdemux.c: (gst_rmdemux_init),
(gst_rmdemux_validate_offset), (gst_rmdemux_loop),
(gst_rmdemux_parse_mdpr), (gst_rmdemux_parse_packet):
When operating in pull mode, post an error message on the
bus when all source pads are unlinked or some other fatal
error occured (#323023). Regrade some recurring debug messages
to LOG level. Convert c++-style comments into C-style ones.