Impacted versions:
* 11.0

Steps to reproduce:
* Create company A
* Create company B
* Admin user with both companies but currently in company B
* Create Demo user only with company B
* Create fiscal position A to company A
* Create fiscal position B to company B
* Create vendor with fiscal position A with company A and the same vendor with fiscal position B in company B
* Create product and add the vendor created before
* Set like **Create a draft purchase order**
* Logging with Demo user
* Create sale order with one sale order line with route **make to order**
* Validate sale order

Current behavior:
The purchase order created by sale order has the fiscal position **company A**

Expected behavior:
The purchase order must have fiscal position **company B**
addons/purchase/models/purchase.py
_inherit = 'procurement.rule'
    @api.model
    def _get_action(self):
        return [('buy', _('Buy'))] + super(ProcurementRule, self)._get_action()
class ProcurementOrder(models.Model):
    _inherit = 'procurement.order'
    purchase_line_id = fields.Many2one('purchase.order.line', string='Purchase Order Line')
    purchase_id = fields.Many2one(related='purchase_line_id.order_id', string='Purchase Order')
    @api.multi
    def propagate_cancels(self):
        result = super(ProcurementOrder, self).propagate_cancels()
        for procurement in self: