fix document service panic
fix document service panic

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