Merge r1491564 from trunk:

const goodness with nasty strrchr and strchr functions
(resolve warning in maintainer mode)

Submitted by: trawick
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1496914 13f79535-47bb-0310-9956-ffa450edef68