Fix for Trac #1573.
This is two bugs. The first is that vorbisfile_example.c ignores an error code and plows ahead blindly if libvorbisfile reports the current bitstream section is bad (OV_EBADLINK). The second is that retrying after the error crashes libvorbisfile due to the unitialized state. svn path=/trunk/vorbis/; revision=16328