Support for OpenSSL 1.1.0

- Simplify code by using new 1.1.0 variant
  also for older OpenSSL. Also tested with
  1.0.2f and 0.9.8zh. No ssl test suite
  failures.

Backport of r1731423 from trunk.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-openssl-1.1.0-compat@1755844 13f79535-47bb-0310-9956-ffa450edef68