fix(ir_attachment_facturae_mx): fix company_id when document is created

think in the next context:

1.- Multicompany environment 2.- The invoice is created from duplicating other one 3.- The current user and the user who created the other invoice are different and are logged in different companies

Thus OpeneERP will crash with permision problem "You cannot read company_id action read ..."

l10n_mx_ir_attachment_facturae/models/ir_attachment_facturae.py

_defaults = {
'state': 'draft',
-       'company_id': lambda self, cr, uid, c:

[Agustín Cruz]

¿Porqué borras este valor por defecto? Creo que esto no es necesario.