test: fix issues for ESLint 2.7.0

PR-URL: https://github.com/nodejs/node/pull/6132


Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: thefourtheye <thechargingvolcano@gmail.com>