Per discussion: should not exit. Should not print to stderr.
Errors are ignored.  Updated doc to reflect that, and the fact
that this function is to be avoided.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

Fix CONF_load_modules to CONF_modules_load.
Document that it calls exit.
Advise against using it now.
Add an error print to stderr.
Reviewed-by: NMatt Caswell <matt@openssl.org>