Steps to reproduce:
1. Create two products A and B that require a serial number
2. Create a product C with no trcking
3. Create a BOM for a A with two components B an C
4. Create a MO for A with qty > 1
5. Check availabiltity and produce the first A
6. Record the SN for the first assembly
Bug: When producing the second assembly, it was not possible to
record the SN for the components.
opw:741316
Goffin Simon
b2ab0a8d50