http-cache: removed http_cache_request_dup()
http-cache: removed http_cache_request_dup()

No need to copy the http_cache_request into a new pool; it is already
allocated in an independent pool by all users.

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy