athena-auto-update does not retry configuring unconfigured packages

[geofft]

athena-auto-update checks aptitude --simulate --assume-yes full-upgrade for the string "0 packages upgraded, 0 newly installed, 0 to remove", and assumes that means that there's nothing to do. This fails to check for the string "The following partially installed packages will be configured:", which often occurs when everything's installed but there are unconfigured things. Importantly, this can cause machines to fall out of -cluster or -workstation if there's a transient upgrade problem that could be fixed with aptitude install by hand.