Fix memory corruption problem with ap_custom_response() function.

The core per-dir config would later point to request pool data
that would be reused for different purposes on different requests.

Submitted by:	Will Lowe
Updated by:     Jeff Trawick
Reviewed by:	stoddard, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@103197 13f79535-47bb-0310-9956-ffa450edef68