Fix bug 1020954 - Don't crash when URL is a 404

@mjschranz can you explain a bit more why you need contentType being undefined when searching? Sounds like you're relying on a bug and we need to help you in a more explicit way.

However, doesn't it make sense for hubble to return an error if someone hits it up with a 404?

Anyway, those are my thoughts. Mostly just nits, I'm not too against this fix, it works, and is better than it was. So r+.