Merge r1501827 from trunk:

* modules/metadata/mod_unique_id.c: Replace use of hostname + pid with
  PRNG output.

Submitted by: jkaluza
Reviewed by: jorton, wrowe, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1812267 13f79535-47bb-0310-9956-ffa450edef68