Kfsio lib: set authentication enabled flag in SetParameters() according to the current settings; add authentication required flag to enforce mutual client / meta server authentication.
Kfs client lib: initialize open ssl globals in the kfs client startup sequence. Fix error handling in SslFilter::CreateCtx() when SSL_CreateCTX() returns 0. Do not issue authenticate rpc if meta server doesn't support authentication and authentication is not required by the client configuration.