[FIX] stock_account: round quantities to UoM precision when updating moves

Have a product P values in FIFO, create an incoming stock move.
Suppose P has UoM U with rounding R, and the stock move has quantity Q.
Edit the quantity done to be Q + e, with e << R.
By the semantic of the UoM rounding, this should mean that no change has been
done. However no such check was done, so the move was updated.
As a result, this would mess up the valuation of P.

opw 2006831

addons/stock_account/models/stock.py

@@ -88,7 +88,10 @@ class StockMoveLine(models.Model):
         if 'qty_done' in vals:
             moves_to_update = {}
             for move_line in self.filtered(lambda ml: ml.state == 'done' and (ml.move_id._is_in() or ml.move_id._is_out())):
-                moves_to_update[move_line.move_id] = vals['qty_done'] - move_line.qty_done
+                rounding = move_line.product_uom_id.rounding
+                qty_difference = float_round(vals['qty_done'] - move_line.qty_done, precision_rounding=rounding)
+                if not float_is_zero(qty_difference, precision_rounding=rounding):
+                    moves_to_update[move_line.move_id] = qty_difference
 
             for move_id, qty_difference in moves_to_update.items():
                 move_vals = {}