Support for OpenSSL 1.1.0:

- further improvements for renegotiation
No more test suite failures for reneg,
but still using not so nice polling.

Backport of r1729927 from trunk.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-openssl-1.1.0-compat@1755829 13f79535-47bb-0310-9956-ffa450edef68