Fix free.law problem with non-functional 404s

[mlissner]

No description provided.

[mlissner]

I"m really not sure how to fix this, but if you look in the netlify logs, you can see what happens when there's a 404. It's a bit annoying. The big effect this was causing was that Google really didn't like us because we didn't have a robots.txt file, so I just added one and that's better.

Still, it'd be nice to have 404's instead of 500's. Kind of insane that we don't, but it's not causing a ton of trouble, so it's not a huge priority for now.