A PUT request should invalidate a previously cached object with the same URI

If the client first fetches an object with GET, and TS caches it, a subsequent PUT request for the same URL should invalidate the cached object.

Update: This is a problem with PUT/POST when the response from the origin is a 201, and there is a Location: header. We then must also invalidate any cached object for the URL which the Location header refers to

(Originally discovered with Coadvisor).