Resolve JS hint errors

Minor touch up so it passes validation
Hey gents! ( @gkindel @kristerkari )

I was using this script for building an app for [Zendesk](https://developer.zendesk.com/apps/docs/agent/introduction). I modified it to be able to pass their [validation for uploading an app](https://support.zendesk.com/hc/en-us/articles/203691236#topic_xkt_j5m_1l) thus I needed to resolve the JS hint errors. I wasn't aware of the implications for changes affecting node.js. Apologies about that, I myself I'm just learning about the ins and outs of JS haven't had a chance to get into node.

Love the script btw, thank you for putting work into creating this! :pray: