Chunk server: fix retire RPC "leak" right before chunk server shutdown by "submitting" the RPC. Change retire trace message level to warning.
Chunk server: fix retire RPC "leak" right before chunk server shutdown by "submitting" the RPC. Change retire trace message level to warning.

quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs