[IMP] l10n_es_ticketbai simplify document schema validation.
[IMP] l10n_es_ticketbai simplify document schema validation.

Instead of raise + except just ask the schema whether a document is
valid: much simpler and cleaner. Also, keeps travis happy by not
logging assertion errors.

factorlibre/l10n-spain,factorlibre/l10n-spain,factorlibre/l10n-spain