When you procure a kit, it doesn't matter what the route configuration
is on the product itself but on its children, so it is not needed to
check anything else but the BoM to assign the 'phantom' supply
method.

Also do not assign a BoM when the supply method is not phantom or manufacture.

After odoo/odoo@1ed6dbe
we need to explicitly set routes in the propoer order becouse while
in the cache there are not yet sorted by sequence (it requires flush
to the database, which we cannot do in a test).