doc: fix dns.lookup options example
doc: fix dns.lookup options example

PR-URL: https://github.com/iojs/io.js/pull/757
Reviewed-By: Brendan Ashworth <2a35967cb8cf8bc6bb9ebf86d18bb6cabb303f5b@me.com>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node