[tor-relays] Reminder: don't run transparent proxies at exits

[Drake Wilson]

eric gisse wrote:
> This isn't exactly a convincing argument.
> 
> The HTTP specification explicitly supports caching.

But the TCP specification doesn't.  Nor is the Tor client signaling
to you that they want an HTTP connection and not a raw TCP connection.
Whether they happen to be passing octets over it that correspond to an
HTTP stream is irrelevant.

   ---> Drake Wilson