fix(storage): avoid data race on table Done channel
fix(storage): avoid data race on table Done channel

Fixes #1021.

mark-rushakoff/influxdb,influxdb/influxdb,nooproblem/influxdb,influxdb/influxdb,influxdata/influxdb,li-ang/influxdb,nooproblem/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,influxdb/influxdb,influxdb/influxdb,influxdata/influxdb,mark-rushakoff/influxdb,li-ang/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,nooproblem/influxdb