Apply some fixes from [comment:14:ticket:19001](https://trac.torproject.org/projects/tor/ticket/19001#comment:14). ([diff](https://trac.torproject.org/projects/tor/wiki/doc/Snowflake?action=diff&version=13)) URL: https://trac.torproject.org/projects/tor/wiki/doc/Snowflake?version=13