Unable to finish a supply on sale shipment with partial supply quantity
On 5.6 series (on trunk the issue is not pressent thanks to #9194 (closed)) it is not possible to finish a customer shipment with assigned and draft moves.
Here are the steps to reproduce:
1. Activate sale_supply module
2. Create a product that supplies on sales
3. Create a sale of 2 units of the product.
4. Create the purchase and process it.
5. Create a supplier shipment and receive 1 unit of the product.
6. Go to the customer shipment and try to set to zero or delete the draft move.
On both cases the following UserError is raised: "To modify stock move "%(move)s" you must reset its state to draft." and it is not possible to continue on it.
I'm not sure how we shold fix this for current series.