[sudo-users] No error message if reading password fails

[R. Diez]

> Point taken; it is hard to tell whether the command was run or not
> in the absence of any kind of message.
 > [...]

This is the first time in many years that I report 2 shortcomings to an 
open-source project, and they get fixed quickly and with a minimum of fuss.

After so much negative experience everywhere else, I wanted to say it, 
just for the record.

Please keep up the good work!

Best regards,
   rdiez