additional, after clicking "Restart Now", we need to disable the "Restart Now" and "Later" buttons, so that the user can't click on them again (while they are dealing with the "confirm close" prompts.
finally, improve the prompt scenario (by first focusing the wizard) where the user has paused in the middle downloading a software update, minimized the software update wizard, and then quit the app.
r=gavin.sharp, sr=mconnor a=beltzner
git-svn-id: svn://10.0.0.236/branches/MOZILLA_1_8_BRANCH@209784 18797224-902f-48f8-a5cc-f745e15eee43
f2d56b6181