Update for alloc_buffer changes.

Update for alloc_buffer changes.

Original commit message from CVS:
2005-12-05  Andy Wingo  <wingo@pobox.com>

* ext/libvisual/visual.c: (get_buffer):
* ext/ogg/gstoggdemux.c: (gst_ogg_demux_chain_peer):
* ext/pango/gsttextrender.c: (gst_text_render_chain):
* ext/theora/theoradec.c: (theora_handle_data_packet):
* ext/theora/theoraenc.c: (theora_buffer_from_packet),
(theora_enc_chain):
* ext/vorbis/vorbisdec.c: (vorbis_handle_data_packet):
* gst/videotestsrc/gstvideotestsrc.c: (gst_video_test_src_create):
Update for alloc_buffer changes.