core: Use the proper macro for HTTP/1.1.

trunk patch: http://svn.apache.org/r1482996
Submitted by: minfrin
Reviewed by: covener, jailletc36


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1483029 13f79535-47bb-0310-9956-ffa450edef68