Comment 4 for bug 13731

Athentication alerts should use the stock authentication icon, which the current
alert does
<http://developer.gnome.org/projects/gup/hig/2.0/windows-alert.html#alerts-authentication>.
But there are other things that could be improved in the current alert:
1. The title should be removed. As noted in comment 0 the current title is
inaccurate; but alerts shouldn't have titles anyway, because (in general, even
if not in particular) they're unhelpfully redundant with the alert text.
<http://developer.gnome.org/projects/gup/hig/2.0/windows-alert.html>
2. The default button would make a bit more sense as "Continue" than as "OK".
3. The Cancel and Continue buttons would be faster to use if they responded to
Cancel and Enter, not Alt+C and Alt+O.
4. The program name should be in quotes (to avoid occasional non-sequiturs),
and could be put earlier in the sentence to ease scanning of the text.

So, something like this:
 ____________________________________________________
|::::::::::::::::::::::::::::::::::::::::::::::::::::|
| |
| _ To run the program "Ubuntu Update Manager", |
| |_| you need to enter your password. |
| |:::| _______________________________ |
| '"""' Password: [_______________________________] |
| |
| ( Cancel ) (( Continue )) |
|____________________________________________________|