Helps in implementation of #6204, where some options passed to
`createSecurePair()` are ignored before this patch.
These options are very helpful if someone wants to pass
`options.servername` or `options.SNICallback` to securepair.
PR-URL: https://github.com/nodejs/node/pull/2441
Reviewed-By: Fedor Indutny <fedor@indutny.com>
