Add route for broken link.

http://neo4j.com/download-thanks/?xxx has a "Get a driver" link that
points to http://neo4j.com/software/, which doesn't exist.
This adds a route to forward to
http://neo4j.com/developer/language-guides/.

@simpsonjulian I couldn't find the link in the repo to fix the link itself, so I added the route. If that's no good, consider this a bug report about the broken link instead :-) Thx.