Upgrade moreutils to 0.52

It appears that 0.51 has been yanked, as it's no longer found at any of the mirrors.

![screen shot 2014-09-23 at 7 37 21 am](https://cloud.githubusercontent.com/assets/30456/4371943/686839b8-431e-11e4-8ceb-66d731fd130f.png)