Fix missing "Fetch" label

This addresses the missing "fetch" label indicating the distinction between `git pull` and `git fetch` as mentioned [here](https://github.com/github/training-kit/issues/83).

The SVG layer was inadvertently hidden in the last update to this SVG, preventing the `fetch` label from appearing in the build steps on the [slide deck](training.github.com/kit/slides/github-foundations.html#/7/1).

![fetch](https://cloud.githubusercontent.com/assets/352082/2737272/dd70b23a-c678-11e3-8c0d-86b24c89d163.png)
![pull](https://cloud.githubusercontent.com/assets/352082/2737273/dd7e193e-c678-11e3-969d-850a4efc786e.png)