Merge r1656230 from trunk

   * mod_proxy_connect: fix duplicated AH introduced by r1635645
      (and merged to 2.4.11 in r1642857)

Submitted by: ylavic
Reviewed by: ylavic, jailletc36, minfrin
Backported by: jailletc36

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1661305 13f79535-47bb-0310-9956-ffa450edef68