Bracket for E3D v6 Fan Duct

I wanted to mount [Neo_Usagi's E3D v6 Duct](http://www.thingiverse.com/thing:814286) to my Prusa i3, which has a [3D LabteK Y-carriage](http://3dlabtek.weebly.com/alu-x-carriiage-rev-02.html), but couldn't make it fit using the supplied bracket. So I quickly cobbled together this version.