Merge 1436401 from trunk:

* support/htcacheclean.c (main): Ensure -p was used before attempting
  to process URL arguments.

Reviewed by: jorton, rpluem, rjung


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1436846 13f79535-47bb-0310-9956-ffa450edef68