Modified adapter to not log error when a route is not absolute

The adapter caching system only works with absolute routes (those than start with '/') if an relative route is used `base/src/module.js` Karma is always logging one error per module.

I did it just by adding '/' to the route if it is not relative, I could've made it more flexible using document.location but I think Karma always opens html files in server's root directory so it's not needed. But I can add it.