Modify post_config hook so that it can return a error,

causing the server not to start.
previous method was to call exit(1) which would not fail
gracefully

PR:
Obtained from:
Submitted by:
Reviewed by:	(Idea only Jeff Trawick)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92144 13f79535-47bb-0310-9956-ffa450edef68