Backport r1421323, r1534754, r1546693, r1555464 from trunk:

Add support for OpenSSL configuration commands by introducing
the SSLOpenSSLConfCmd directive.

Proposed by: kbrand
Reviewed by: drh, trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1555683 13f79535-47bb-0310-9956-ffa450edef68