设备运行时长，改bug

src/main/java/org/rcisoft/business/device/assets/service/impl/BusDeviceServiceImpl.java

@@ -201,7 +201,10 @@ public class BusDeviceServiceImpl implements BusDeviceService {
             }
         });
         //更新结果
-        return busDeviceRepository.batchUpdateRunTm(saveList);
+        if (saveList.size() > 0)
+            return busDeviceRepository.batchUpdateRunTm(saveList);
+        else
+            return 0;
     }
 
 }