[FIX] procurement: refactor scheduler so it continues even if a procurement failed

If the mrp scheduler fails during the treatment of a procurement (due to a postgresql error, like an update lock), we let it try the other procurements, instead of stopping at the first procurement which fails.
Besides, we retry to treat the procurements which failed, until the list of the remaining procurements is always the same (meaning something is wrong and block the procurements treatment).
[FIX] l10n_be_coda: set a meaningful filename default value