saleorderModel

Fix saleorder update wste an inactive na mhn krataei thn prwth, alla na
pataei panw ths, enw an active na krataei thn prwth.
Pros8hkh activateSaleOrder, wste na ginei active mia inactive saleorder
gia na mporei pleon na thn blepei o apo8hkarios kai na mporei na
ektelestei.