[bug 826757] Track user type in Google Analytics. 

r?

To test this out, log in to the site. On the first page after logging in, you should see something like `data-ga-push="[[&#34;_setCustomVar&#34;, 1, &#34;User Type&#34;, &#34;Contributor - Admin&#34;, 1]]"` on `<body/>` as an attribute. Also if you look at the requests (Net tab in dev tools), you should see a request like: `[14:13:04.558] GET http://www.google-analytics.com/__utm.gif?...&utme=8(User%20Type)9(Contributor%20-%20Admin)11(1)&...`. The User Type can be seen in the query params to google analytics.