When OPENSSL_LOAD_CONF was added it ended up with more #if 0 code,
more #ifdefs and a new source file that contains a single function.

Nuke the #if 0 code that is now a macro and move the single function in
evp_acnf.c to c_all.c, which is where the other code lives. While here,
tidy evp.h slightly, remove an unnecessary #ifdef __OpenBSD__ and nuke
a comment that is now a lie.

ok miod@
define LIBRESSL_INTERNAL, and use it to hide the bad stuff from ourselves
ok beck
"for every change..."