[FIX] account_voucher: fix missing payment_id in "Pay Directly" voucher

Create an accout.voucher with "Pay Directly" as payment.
    You get something like:

                D  |  C
    --------------------
    Expenses:   x  |
    Cash:          |  x

    However, the expense line doesn't appear in the reconciliation widget
    because the payment_id is missing in the account.move.line and then, doesn't match
    the search domain for the reconciliation.

    To solve it, a payment_id is created for this line in case of "Pay Directly" payment.

    -opw: 775167

addons/account_voucher/models/account_voucher.py

@@ -183,6 +183,7 @@ class AccountVoucher(models.Model):
                     if company_currency != current_currency else 0.0),
                 'date': self.account_date,
                 'date_maturity': self.date_due
+                'payment_id': self._context.get('payment_id'),
             }
         return move_line
 
@@ -221,6 +222,24 @@ class AccountVoucher(models.Model):
         for voucher in self:
             return voucher.currency_id.compute(amount, voucher.company_id.currency_id)
 
+    @api.multi
+    def voucher_pay_now_payment_create(self):
+        payment_methods = self.journal_id.outbound_payment_method_ids
+        return {
+            'payment_type': 'outbound',
+            'payment_method_id': payment_methods and payment_methods[0].id or False,
+            'partner_type': 'supplier',
+            'partner_id': self.partner_id.id,
+            'amount': self.amount,
+            'currency_id': self.currency_id.id,
+            'payment_date': self.date,
+            'journal_id': self.journal_id.id,
+            'company_id': self.company_id.id,
+            'communication': self.name,
+            'name': self.name,
+            'state': 'reconciled',
+        }
+
     @api.multi
     def voucher_move_line_create(self, line_total, move_id, company_currency, current_currency):
         '''
@@ -258,8 +277,8 @@ class AccountVoucher(models.Model):
                 'tax_ids': [(4,t.id) for t in line.tax_ids],
                 'amount_currency': line.price_subtotal if current_currency != company_currency else 0.0,
                 'currency_id': company_currency != current_currency and current_currency or False,
+                'payment_id': self._context.get('payment_id'),
             }
-
             self.env['account.move.line'].with_context(apply_taxes=True).create(move_line)
         return line_total
 
@@ -279,6 +298,9 @@ class AccountVoucher(models.Model):
             ctx = local_context.copy()
             ctx['date'] = voucher.account_date
             ctx['check_move_validity'] = False
+            # Create a payment to allow the reconciliation when pay_now = 'pay_now'.
+            if self.pay_now == 'pay_now' and self.amount > 0:
+                ctx['payment_id'] = self.env['account.payment'].create(self.voucher_pay_now_payment_create()).id
             # Create the account move record.
             move = self.env['account.move'].create(voucher.account_move_get())
             # Get the name of the account_move just created