[packagekit] exclude some upgrades

[Richard Hughes]

On Mon, 2007-11-12 at 15:48 -0500, Matthias Clasen wrote:
> I mean the severity icons in the update viewer. Ideally, the icons
> would be clear enough to convey the severity without a tooltip...

I'm guessing I should be using gtk_tree_view_set_tooltip_cell, although
google code search isn't much help with actually using this. Code
snippet welcome. Cheers dude.

Richard.