Stop JS from rendering outside of head tag

When I moved to the govuk_admin_template I accidentally left some things outside of content_for tags which meant that there were a whole bunch of script tags at the top of the page before the <head> this caused ie^ and 7 to get very confused, naturally.

Before
![before](https://cloud.githubusercontent.com/assets/68009/3387468/8f4f9a6c-fc7e-11e3-8486-feb3bd576dbf.png)

After
![after](https://cloud.githubusercontent.com/assets/68009/3387469/91226cca-fc7e-11e3-8ee6-431f9ff058f3.png)