[Ur] fix returnBlob and redirect in static protocol

[Adam Chlipala]

Thanks; patch accepted.  It might be better to submit such patches on 
the Ur/Web Mantis bug tracker in the future.

On 07/13/2015 02:37 PM, Julian Squires wrote:
> Patch attached.  (Justification: I'm emitting Test Anything Protocol
> as text/plain from a -protocol static build of an application for
> consumption by an existing unit test framework.)