Bug #2028: Segmentation fault on http_reply_access deny

Bug #2028: Segmentation fault on http_reply_access deny

http_reply_access deny triggered an infinite recursion, eventually ending
up in a segmentation fault.

This patch builds on the previous patch to also exclude http_reply_access
deny error responses from further http_reply_access processing.

Note: When a request is denied by http_reply_access the internal client is
reset to attach it to the error page instead, making http_reply_access be
invoked again on the error.