Right now it's a duplicate (not even a symlink) of the favorite icon, which is
semantically inaccurate. A more appropriate visual metaphor is "download", since that's
what GHNS will do. So this patch symlinks the GHNS icon to edit-download. This makes
it work for icons-only buttons as well, where the icon alone is sufficient to communicate
what will happen.
Thanks for @ndavis for suggesting this.
BUG: 400500
FIXED-IN: 5.64