eet: Fix 'No OPENSSL_Applink' error message.

eet: Fix 'No OPENSSL_Applink' error message.

In some systems (such as Windows), OpenSSL raises an error about "No Applink"
(see ["I've compiled a program under Windows and it crashes: why?" in OpenSSL
FAQ](https://www.openssl.org/docs/faq.html#PROG3)). Including only
openssl/applink.c didn't work, so the solution was to replace `FILE*`
interfaces with OpenSSL's BIO API which also contains file operations.

Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Reviewed-by: Stefan Schmidt <stefan@datenfreihafen.org>
Differential Revision: https://phab.enlightenment.org/D12103