OpenSSL: Automatically enable PKCS#11 engine where it's needed

OpenSSL: Automatically enable PKCS#11 engine where it's needed

It needs to be available to ENGINE_by_id(), which in my case means it
needs to be /usr/lib64/openssl/engines/libpkcs11.so. But that's a system
packaging issue. If it isn't there, it will fail gracefully enough with:

ENGINE: engine pkcs11 not available [error:25066067:DSO support routines:DLFCN_LOAD:could not load the shared library]
TLS: Failed to set TLS connection parameters
EAP-TLS: Failed to initialize SSL.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>