When git_filter_list_stream_data() calls stream_list_init() and it fails, stream_start will be set to NULL.

Before returning, git_filter_list_stream_data() always executes close_error = stream_start->close(stream_start); which will obviously crash if stream_start is NULL.

The fix is obvious but what it should be depends on what's the resolution for #4062, which is why I'm not providing a patch at this time.

PS: This was observed on 805b90a.