Support for OpenSSL 1.1.0:

- followup to r1728909 (incomplete switch
  from struct to struct pointer).

Partial backport of r1728979 from trunk.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-openssl-1.1.0-compat@1755816 13f79535-47bb-0310-9956-ffa450edef68