gst/playback/: Fix playback of multiple files. a slightly different approach to handl...

gst/playback/: Fix playback of multiple files. a slightly different approach to handling dynamic pad removals.

Original commit message from CVS:
* gst/playback/gstdecodebin.c: (gst_decode_bin_class_init),
(try_to_link_1), (get_our_ghost_pad), (remove_element_chain),
(unlinked), (no_more_pads), (close_link):
* gst/playback/gstplaybasebin.c: (gst_play_base_bin_init),
(unknown_type), (add_element_stream), (new_decoded_pad),
(removed_decoded_pad), (setup_source):
* gst/playback/gststreaminfo.c: (gst_stream_info_get_type),
(gst_stream_info_class_init), (gst_stream_info_init),
(gst_stream_info_new), (gst_stream_info_dispose),
(stream_info_mute_pad), (gst_stream_info_set_property),
(gst_stream_info_get_property):
* gst/playback/gststreaminfo.h:
Fix playback of multiple files.
a slightly different approach to handling dynamic pad removals.
This one only looks at pads that we have linked.