Remove ENABLE_CRYPTO

Remove ENABLE_CRYPTO

The crypto engine cannot be disabled anymore, therefore get
rid of all the related ifdefs in the code.

This change makes the code simpler and reduces our the
number of config combinations we have to test after a new
change is applied.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Steffan Karger <steffan.karger@fox-it.com>
Message-Id: <20171204010110.22091-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg16004.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>