清除UID时 ，判断iot证书存在时同时清空

Controller/SerialNumberController.py

@@ -354,7 +354,9 @@ class SerialNumberView(View):
             if uid_serial_qs.exists():
                 uid_serial = uid_serial_qs[0]
 
-                iotdeviceInfoModel.objects.filter(serial_number__serial_number=serial).delete()
+                iot = iotdeviceInfoModel.objects.filter(serial_number__serial_number=serial)
+                if iot.exists():
+                    iot.delete()
 
                 company_serial_qs = CompanySerialModel.objects.filter(id=uid_serial.company_serial.id)
                 if company_serial_qs.exists():