Client library: fix chunk server and chunk access tokens retrieval with lease acquisition and renewal by resetting chunk access tokens before re-acquiring the lease in order to prevent using stale chunk access tokens obtained by the last lease renewal.
Client library: fix chunk server and chunk access tokens retrieval with lease acquisition and renewal by resetting chunk access tokens before re-acquiring the lease in order to prevent using stale chunk access tokens obtained by the last lease renewal.

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