Merge r1422549, r1422712 from trunk:

add new ap_bin2hex() utility function


remove unnecessary cast

Submitted by: sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1439390 13f79535-47bb-0310-9956-ffa450edef68