不够3个单，不算平均数

AutoTurnOver.Services/PurchaseAverageTargetServices.cs

@@ -106,6 +106,12 @@ namespace AutoTurnOver.Services
 
                         task_log.Count++;
                     }
+                    else
+                    {
+                        // 不够3个单，不该有平均数
+                        data.delivery_days = 0;
+                        AveragePurchase.Save(data, conn);
+                    }
 
                     var purchaseWList = AveragePurchase.GetPurchaseListByWode(skuItem, _seed_count).ToList();