Merge r1644498 from trunk

   * mod_ssl: Fix renegotiation failures redirected to an ErrorDocument.
              (segfault flaw) PR 57334.

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

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1662640 13f79535-47bb-0310-9956-ffa450edef68