[sudo-workers] display_privs return value

[Todd C. Miller]

OK, you've convinced me.

 - todd

https://www.sudo.ws/repos/sudo/rev/055b78015fcb

Go back to returning true from display_privs() on non-error.  This
results in "sudo -U otheruser -l" exiting with a status of 0 even
when otheruser is not allowed to run commands.  This is appropriate
since the "sudo -l" command was successful.  This does not change
the exit value when otheruser runs "sudo -l" themselves, the exit
status will be 1 since that user is not allowed to run commands.