KclMessageDrivenChannelAdapter must not shutdown Worker in the stop()

[artembilan]

We can't perform a this.scheduler.shutdown() in the KclMessageDrivenChannelAdapter.stop() because Worker is not going to be restarted on the next start() call. Probably this is a serious problem and has to be back-ported to the previous version. See a DisposableBean implementation on the KinesisMessageDrivenChannelAdapter.