Merge r1457450, r1457610, r1457995, r1458003 from trunk:

Expression parser: Add the ability to apply a SHA1 hash to strings within
the parser.


Expression parser: use hex encoding for the sha1 hash.


sha1 now does hex encoding


simplify code by using ap_bin2hex()

Submitted by: minfrin, sf, sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1467979 13f79535-47bb-0310-9956-ffa450edef68