When `influx_inspect buildtsi` is used to create a new `tsi1` index, spaces in measurement names are escaped, so measurement "a b" is changed to "a\ b".
This change modifies `models.ParseKeyBytes()` and `models.ParseName()` to unescape measurement names. `models.ParseKeyBytes()` returns unescaped tag keys, so this seems like the natural place to unescape measurement names.
Also followed `scanMeasurement()` to see what other code could be problematic, and this should be everything (the result of one other use of `scanMeasurement()` is later escaped).
Removed `tsdb.MeasurementFromSeriesKey()`. These methods are exported, so checked for side effects in other InfluxData repositories.
44c5da060b