Redmine#6109: Make CFEngine able to compile on old OpenSSL implementatio...

...ns by assuming sane defaults, and aborting if they are not.

Ticket: https://dev.cfengine.com/issues/6109
I'm a little bit worried what this might do if you for example do a system upgrade, happily unaware that OpenSSL is now going to blow up all your CFEngine agent nodes. How about instead of programming error, we do a ``Log(LOG_LEVEL_CRIT, "bla bla")``. That's the highest verbosity level, so we should capture the admin's attention, but at least CFEngine won't die.

I would also like to see a message that gives the user a better idea of what to do, for example: ``This version of CFEngine was compiled against OpenSSL < 0.9.8m. Using it with a later version is insecure. Please recompile CFEngine against the new OpenSSL version, or obtain a newer package.``