Merge r1494952 from trunk:

Document apxs -p paramter.

Submitted by: Jan Kaluža <jkaluza@redhat.com>
Reviewed by: covener




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1494953 13f79535-47bb-0310-9956-ffa450edef68