Fix return value of "sudo -l command" when command is not allowed, broken

Fix return value of "sudo -l command" when command is not allowed, broken
in [c7097ea22111].  The default return value is now TRUE and a bad:
label is used when permission is denied.  Also fixed missing permissions
restoration on certain errors.  On error()/errorx(), the password and
group files are now closed before returning.

--HG--
branch : 1.8