Routines for handling system-wide validators
      use NethServer::Validation;
      my $exitcode = NethServer::Validation::validate($validator, @args);


  Searches for all validator scripts inside the validator directory,
  '/etc/e-smith/validators' then executes them.
  A successful validation occurs when all scripts return 0 (success
  validation) or at least one script returns 2 (sufficient valid condition).
  Otherwise validation fails.
  Each script in the validator directory must return one of these exit
    0: successful validation
    1: validation failed (generic)
    2: sufficient validation (successful)
    3..255: failed with specific reason
  When a script returns 2 (sufficient validation) no further script will be
  processed and the validate() is successful.
  Scripts are not supposed to generate error messages under normal
  conditions, so we do not provide a mechanism for validator handlers to
  signal errors to the user. Errors can only be written to the log file.
Return value
  The validate() function returns 0 on failure, 1 on success.
perldoc NethServer::Directory