Code review comment for lp:~bac/launchpad/bug-799901

Thanks for the suggestion Danilos. I've made the change you suggested. I did go ahead and update the model as Robert suggested just because I think it is better practice to do the comparisons the most efficient way even if the objects are cached so that someone else wouldn't pattern a new change off the inefficient approach.

I also added a test showing the query count for getting the direct subscribers is 1. This required a slight refactoring of the browser property.