[17.0][FIX] delivery_roulier: fix AttributeError...is_roulier

[imlopes]

self.carrier_id.with_context(order_weight=self.total_weight).rate_shipment(self.order_id)
  File "/odoo/external-src/delivery-carrier/delivery_roulier/models/delivery_carrier.py", line 47, in rate_shipment
    if not res and self.is_roulier():
AttributeError: 'delivery.carrier' object has no attribute 'is_roulier'

[OCA-git-bot]

Hi @florian-dacosta, some modules you are maintaining are being modified, check this out!

[rousseldenis]

@imlopes Thanks for this. Isn't it possible to add a test that return nothing for super() in rate_shipment() in order to avoid future regressions ?