fix for when no args are passed to cli

When no args are passed to the cli we get this error message:

```javascript
timers.js:103
            if (!process.listeners('uncaughtException').length) throw e;
                                                                      ^
TypeError: Cannot call method 'apply' of undefined
    at Object.runAction [as _onTimeout] (/Users/leetreveil/Dropbox/bstest/node_modules/browserstack-cli/bin/cli.js:452:10)
    at Timer.list.ontimeout (timers.js:101:19)
```