wmaker: improve error messages when trying to start the helper
Try to provide better messages to understand what went wrong, including
more information, and made them translatable;
Changed the call to 'dup' into 'dup2' which has a safer behaviour because
we can specify the target descriptor we want;
Removed a few check for the 'close()' because in these cases we do not
really care if they fail (we can't do anything about it and it just adds
noise in the logs).
Signed-off-by: Christophe CURIS <christophe.curis@free.fr>
Signed-off-by: Carlos R. Mafra <crmafra@gmail.com>