Support compilation against libssl built with OPENSSL_NO_SSL3.

backport https://svn.apache.org/r1706008 from 2.4.x

Submitted by: kbrand
Reviewed by: ylavic, wrowe, covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1777494 13f79535-47bb-0310-9956-ffa450edef68