Merge r1774602 from trunk:

Use correct format pattern, "%lu" is wrong for
apr_uint64_t on some platforms.

Followup to r1649491.

Submitted by: rjung
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1774625 13f79535-47bb-0310-9956-ffa450edef68