Merge r1433988 from trunk:

* A limit of zero means unlimited for LimitRequestBody.

PR: 54435
Submitted by: Pavel Mateja <pavel netsafe.cz>
Reviewed by: rpluem

Submitted by: rpluem
Reviewed by: rpluem, jim, jorton


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1436443 13f79535-47bb-0310-9956-ffa450edef68