Clear the shipwire_id field even if the cancel API throws an error
Clear the shipwire_id field even if the cancel API throws an error

Previously the shipwire_id wasn't cleared if the cancel API threw an
error. This caused an issue when the related shipwire entity was already
deleted but the shipwire_id was still present because in this scenario
the API returns a `422 - Order cannot be cancelled`.

nebulab/solidus_shipwire,nebulab/solidus_shipwire,nebulab/solidus_shipwire