Merge r1682482 from trunk:

PR 57968: Don't lowercase the argument to SetHandler if the handler is
proxy:unix.


Submitted by: covener
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1682888 13f79535-47bb-0310-9956-ffa450edef68