[FIX] l10n_fr_certification: write on move should a little bit more d…

…efensive

Before this commit, we tried to assign new hash and seq number bu the method
obj.key = new value which triggers a write on obj, and we find ourselves in a loop

After this commit, first only moves that do not have hash and sequence number are selected
and second, super.write is called to avoid getting back in our very same write function

Development issue by PNA and LAP on bank statements validation

addons/l10n_fr_certification/models/account.py

@@ -80,10 +80,12 @@ def write(self, vals):
         res = super(AccountMove, self).write(vals)
         # write the hash and the secure_sequence_number when posting an account.move
         if has_been_posted:
-            for move in self.filtered(lambda m: m.company_id.country_id.code == 'FR'):
+            for move in self.filtered(lambda m: m.company_id.country_id.code == 'FR' and
+                                      not (m.l10n_fr_secure_sequence_number or m.l10n_fr_hash)):
                 new_number = move.company_id.l10n_fr_secure_sequence_id.next_by_id()
-                move.l10n_fr_secure_sequence_number = new_number
-                move.l10n_fr_hash = move._get_new_hash(new_number)
+                vals_hashing = {'l10n_fr_secure_sequence_number': new_number,
+                                'l10n_fr_hash': move._get_new_hash(new_number)}
+                res |= super(AccountMove, move).write(vals_hashing)
         return res
 
     def button_cancel(self):