Chunk server: fix storage tiers update in NotifyMetaChunksLost(), do not attempt to update tiers if directory is already marked not in use.
Chunk server: fix storage tiers update in NotifyMetaChunksLost(), do not attempt to update tiers if directory is already marked not in use.

chanwit/qfs,quantcast/qfs,thebigbrain/qfs,fengshao0907/qfs,qnu/qfs,quantcast/qfs,fengshao0907/qfs,chanwit/qfs,chanwit/qfs,quantcast/qfs,thebigbrain/qfs,fengshao0907/qfs,thebigbrain/qfs,thebigbrain/qfs,chanwit/qfs,qnu/qfs,quantcast/qfs,fengshao0907/qfs,fengshao0907/qfs,quantcast/qfs,thebigbrain/qfs,quantcast/qfs,chanwit/qfs,thebigbrain/qfs,qnu/qfs,chanwit/qfs,quantcast/qfs,fengshao0907/qfs,thebigbrain/qfs,fengshao0907/qfs,fengshao0907/qfs,thebigbrain/qfs,chanwit/qfs,qnu/qfs,qnu/qfs,quantcast/qfs,qnu/qfs,chanwit/qfs,qnu/qfs,qnu/qfs