Ensure series keys are sorted
Ensure series keys are sorted

The Measurement added series keys from a map where the iteration
order is non-deterministic.  The keys should be returned in sorted
order.

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