ext/: Fix a small memory leak in vorbisenc.

ext/: Fix a small memory leak in vorbisenc.

Original commit message from CVS:
* ext/ogg/gstoggmux.c: (gst_ogg_mux_clear), (gst_ogg_mux_init),
(gst_ogg_mux_sinkconnect), (gst_ogg_mux_request_new_pad),
(gst_ogg_mux_push_buffer), (gst_ogg_mux_dequeue_page),
(gst_ogg_mux_pad_queue_page), (gst_ogg_mux_queue_pads),
(gst_ogg_mux_set_header_on_caps), (gst_ogg_mux_collected),
(gst_ogg_mux_clear_collectpads), (gst_ogg_mux_change_state):
* ext/vorbis/vorbisenc.c: (gst_vorbisenc_buffer_from_packet),
(gst_vorbisenc_change_state):
Fix a small memory leak in vorbisenc.
Fix large memory leaks in oggmux, also fix lots of state change
bugs in oggmux.