Drop support for OpenSSL 1.0.1

Drop support for OpenSSL 1.0.1

OpenSSL 1.0.1 was supported until 2016-12-31. Rhel6/Centos6 still
use this version but considering that RHEL7 and RHEL8 are already
out, these versions can also stay with OpenVPN 2.4.

All the supported Debian based distributions also come with at
least 1.0.2.

We (accidently) unconditionally compiled some key exporter code on
OpenSSL 1.0.2+ without problems. So always compile the whole
key exporter feature for OpenSSL.

This also allows the tls groups commit to be applied without
adding ifdefs to disable that functionality on OpenSSL 1.0.1

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Steffan Karger <steffan.karger@foxcrypto.com>
Message-Id: <20200717134739.21168-2-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20441.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>