OpenSSL: don't use direct access to the internal of X509_OBJECT

OpenSSL: don't use direct access to the internal of X509_OBJECT

OpenSSL 1.1 does not allow us to directly access the internal of
any data type, including X509_OBJECT. We have to use the defined
functions to do so.

Compatibility with OpenSSL 1.0 is kept by defining the corresponding
functions when they are not found in the library.

Signed-off-by: Emmanuel Deloget <logout@free.fr>
Acked-by: Steffan Karger <steffan.karger@fox-it.com>
Message-Id: <c849c9778d2b2faa4eb4d31367b37d993da5eb85.1487368114.git.logout@free.fr>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14080.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>