No nav links on Sourcegraph.com for unauthed users

Created by: sqs

I know we've been fixing issues in this code recently. I found another regression. As an unauthed user, there are no about/sign-in links. There should be on Sourcegraph.com. I think this is a simple bug where the NavLinks component is not being shown (and when it's shown, it will show the correct set of links).