configuration change.

allow a '!' directive to stop proxying these requests
eg.

  ProxyPass /services/images/     !
  ProxyPass /services/            http://service-machine/services/

which will stop requests to /services/images/ from being proxied

Submitted by:	Jukka Pihl <jukka.pihl@entirem.com>
Reviewed by:	Ian Holsman, Graham Legget, Chuck Murcko


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93086 13f79535-47bb-0310-9956-ffa450edef68