Health value is used to determine route.
In case of device failure, the value is periodically decremented by recovery process and
after restration of the device, the value is incremented periodically.
But, normal route is not selected until the value will be restored.
We think the value should not be decremented by recovery process,
because it takes time to be restored to its original value.
We stopped health value decrement at recovery processing after a device failure is detected