gst/playback/gstplaybasebin.c: Actually clean up streaminfo if output fails. This...

gst/playback/gstplaybasebin.c: Actually clean up streaminfo if output fails. This would trigger if, for example, ther...

Original commit message from CVS:
* gst/playback/gstplaybasebin.c: (setup_source),
(gst_play_base_bin_change_state):
Actually clean up streaminfo if output fails. This would trigger
if, for example, there was no CD in the drive. No preroll, so
a streaminfo structure is created, but the subsequent state change
of the thread fails.
* gst/playback/gstplaybin.c: (gst_play_bin_change_state):
Don't change state if parent failed.