Fix list view's scrolling div height

I modified the totalHeight computed property in list_view.coffee to always return the calculated total height.

I could not think of a use case where you would need the scrolling div to be taller than the content in the list. I made this modification because IE was incorrectly calculating the height for the scrolling div when there were only a few items in the list, causing a scroll bar to appear when it wasn't necessary. The scrolling div's height now always accurately reflect the number of items, as I believe it should.

Please let me know if there is a use case I'm missing, otherwise this should be an acceptable fix.