#706 Build fails on openssl 1.1

[Chris West (Faux)]

Openssl 1.1, which many distros are moving to, has dropped support for the MD2 hash algorithm by default. This causes the openhpi build to fail against openssl 1.1.

The autoconf build attempts to detect the presence of MD2 by checking if the header exists. Unfortunately, on 1.1, the header exists, but it's not active as OPENSSL_NO_MD2 is defined.

Simply removing the check for the MD2 header happens to cause the code to do the right thing, as in the attached patch, but maybe checking the OPENSSL_NO_MD2 would be more useful? Or simply dropping the MD2 code entirely. It's been 26 years. Let it die.

Debian bug: https://bugs.debian.org/859543