Update for stream lock API changes: don't take stream log in sink event handlers any longer and change GST_STREAM_LOC...

Original commit message from CVS:
* ext/dv/gstdvdemux.c: (gst_dvdemux_handle_sink_event):
* ext/flac/gstflacdec.c: (gst_flacdec_loop),
(gst_flacdec_src_event):
* ext/flac/gstflacenc.c: (gst_flacenc_sink_event):
* ext/ladspa/gstsignalprocessor.c: (gst_signal_processor_event),
(gst_signal_processor_getrange), (gst_signal_processor_chain):
* gst/avi/gstavidemux.c: (gst_avi_demux_handle_seek):
* gst/flx/gstflxdec.c: (gst_flxdec_src_event_handler),
(gst_flxdec_sink_event_handler):
* gst/matroska/matroska-demux.c:
(gst_matroska_demux_handle_seek_event):
* gst/wavparse/gstwavparse.c: (gst_wavparse_handle_seek):
Update for stream lock API changes: don't take stream log
in sink event handlers any longer and change GST_STREAM_LOCK
to GST_PAD_STREAM_LOCK. Don't leak references in flxdec event
functions.