[FIX] account: reconcile on move reversal

Make an invoice for partner X
Make a payment from partner X (not using the register payment button)
On the invoice, you'll see your payment proposal

Now, reverse the move of the payment

Before this commit:
On the invoice you *still have* the payment proposal
This is because nothing reconciled the reversed entries with the original ones when they were created

After this commit:
The reversed moves are reconciled one on one with their original counterparts
And the original payment doesn't show up anymore on the invoice's proposal

OPW 1816462
OPW 1816641

addons/account/models/account_move.py

@@ -211,6 +211,15 @@ class AccountMove(models.Model):
             raise UserError(_("Cannot create unbalanced journal entry."))
         return True
 
+    # Do not forward port in >= saas-14
+    def _reconcile_reversed_pair(self, move, reversed_move):
+        amls_to_reconcile = move.line_ids + reversed_move.line_ids
+        accounts_reconcilable = amls_to_reconcile.mapped('account_id').filtered(lambda a: a.reconcile)
+        for account in accounts_reconcilable:
+            amls_for_account = amls_to_reconcile.filtered(lambda l: l.account_id.id == account.id)
+            amls_for_account.reconcile()
+            amls_to_reconcile = amls_to_reconcile - amls_for_account
+
     @api.multi
     def reverse_moves(self, date=None, journal_id=None):
         date = date or fields.Date.today()
@@ -225,6 +234,7 @@ class AccountMove(models.Model):
                     'credit': acm_line.debit,
                     'amount_currency': -acm_line.amount_currency
                     })
+            self._reconcile_reversed_pair(ac_move, reversed_move)
             reversed_moves |= reversed_move
         if reversed_moves:
             reversed_moves._post_validate()