Fix for Pinterest mobile share overlay

Some last minute svg optimising removed the height and width tags from the svgs. This replaces them, which is in line with our other svg files.

Fix for:
![screen shot 2014-11-04 at 10 45 38](https://cloud.githubusercontent.com/assets/2236852/4898361/bdda87fe-640f-11e4-9a19-0dddcd182ff0.png)