Hide OPENSSL_INIT_SETTINGS.

Make OPENSSL_INIT_SETTINGS an opaque structure.
Reviewed-by: Richard Levitte <levitte@openssl.org>

ssl/ssl_init.c

@@ -294,6 +294,7 @@ static void ssl_library_stop(void)
     }
 }
 
+
 /*
  * If this function is called with a non NULL settings value then it must be
  * called prior to any threads making calls to any OpenSSL functions,