remove a misleading comment

technically true, but this entire method is on a separate thread now
avoid manual management of iconLoadedSet

Too error prone, and as long as the setter is being explicitly defined,
we might as well use it for something.
always take the resolved object's icon

Since loadIcon often does work on another thread and doesn't set a new
icon immediately, there's no point to testing the image, or calling
loadIcon first for that matter. Just blindly take the resolved object's
icon. It will get replaced if needed when loadIcon finishes.
Merge pull request #1438 from skurfer/bgIconLoading

Additional icon loading stuff