[FIX] sale: change qty updates weight

The method `product_id_change` has become quite a mess with time as it
gathers a lot of onchanges. Therefore, previous commits were made in
order to prevent unwanted side effects, such as af07b2a0, 1cedcf6a and
136bd723.

This revision fixes the weight which was lost with commit af07b2a0.

opw-658712

addons/sale/sale.py

@@ -1173,10 +1173,10 @@ class sale_order_line(osv.osv):
             price = Product.price_get(cr, uid, [product], ptype='list_price', context=ctx_product)[product] or False
         price = self.pool['account.tax']._fix_tax_included_price(cr, uid, price, taxes, result['tax_id'])
         if context.get('uom_qty_change', False):
-            product_uos_qty = result.get('product_uos_qty')
-            result, domain = {}, {}
-            if product_uos_qty:
-                result['product_uos_qty'] = product_uos_qty
+            # Remove unnecessary changes
+            domain = {}
+            for key in ["name", "product_uom", "product_uos", "tax_id"]:
+                result.pop(key, None)
         result.update({'price_unit': price})
         return {'value': result, 'domain': domain}