use apr-util's apr_date_parse_http() instead of the to-be-removed

ap_parseHTTPdate()

(proxy needs to make similar changes)

build changes forthcoming...

Submitted by:	Justin Erenkrantz


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89277 13f79535-47bb-0310-9956-ffa450edef68