[FIX] payment: create payment transaction without partner_id
[FIX] payment: create payment transaction without partner_id

The field partner id is not a required field in payment transaction, and
we try to read its value in the dictionnary given to the create
function, so if a transaction is created without the partner_id, it will
raise a KeyError.

So to fix it, we only complete the pratner values on the payment
transaction if a partner_id is given.
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo