libressl fix for removed ENGINE_CTRL_CHIL_SET_FORKCHECK

Submitted By: Stuart Henderson <sthen openbsd.org>
Commited By: covener




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1673455 13f79535-47bb-0310-9956-ffa450edef68