Fix sed regex for generating ap_config_auto.h in src/Configure.

Submitted by: Jan Gallo <gallo@pvt.sk>
Reviewed by: Ralf S. Engelschall
PR: 3690, 4373


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@83215 13f79535-47bb-0310-9956-ffa450edef68