Composer lock review for known vulnerabilities

![screen shot 2014-08-21 at 09 40 12 pm](https://cloud.githubusercontent.com/assets/51677/4003126/734a6bcc-2973-11e4-9b90-82d3ea2c971f.png)
So I actually had an additional check for `file_exists` on the executable, but that wasn't so testable.