storage_proxy: Stop latency_counter before throwing
storage_proxy: Stop latency_counter before throwing

kjniemi/scylla,duarten/scylla,scylladb/scylla,kjniemi/scylla,scylladb/scylla,scylladb/scylla,raphaelsc/scylla,scylladb/scylla,avikivity/scylla,raphaelsc/scylla,avikivity/scylla,duarten/scylla,avikivity/scylla,raphaelsc/scylla,kjniemi/scylla,duarten/scylla