OpenSSL returns an error for SSL_accept() if TLS_client_method()
was used to generate the context (LibreSSL doesn't care).
Prior to sudo 1.9.7, TLS_client_method() and TLS_server_method()
were used in the TLS client and server initialization code respectively.
This was refactored in sudo 1.9.7 to allow the code to be shared.
Bug #988