Fix unhandled routes not resulting in a server round-trip.

There was a relatively recent change that made it (to my eyes) impossible to end up with an unhandled route: https://github.com/visionmedia/page.js/commit/afd036a365de87451e7381d8f36b2931be061038

I made it so we don't bother checking an impossible boolean (ctx.unhandled cannot be true at the point it's being checked) and in the unhandled() method, we do not bother comparing the current location to the context before proceeding.