Missing string values for CacheStatus type

[e-dard]

The metric used to track the reason why the Cache was snapshotted is not stringifying the reason label properly. The values used in the label are defined here:

influxdb/tsdb/tsm1/engine.go

Lines 905 to 917 in 732c0cc

	// CacheStatus describes the current state of the cache, with respect to whether
	// it is ready to be snapshotted or not.
	type CacheStatus int
	// Possible types of Cache status
	const (
	CacheStatusOkay CacheStatus = iota // Cache is Okay - do not snapshot.
	CacheStatusSizeExceeded // The cache is large enough to be snapshotted.
	CacheStatusAgeExceeded // The cache is past the age threshold to be snapshotted.
	CacheStatusColdNoWrites // The cache has not been written to for long enough that it should be snapshotted.
	CacheStatusRetention // The cache was snapshotted before running retention.
	CacheStatusFullCompaction // The cache was snapshotted as part of a full compaction.
	)

It looks like go generate needs to be run again for the stringer

//go:generate stringer -type=CacheStatus

This is the current situation:

storage_compactions_total{engine_id="x",level="snapshot",node_id="0",reason="CacheStatus(4)",status="ok"} 12
storage_compactions_total{engine_id="x",level="snapshot",node_id="0",reason="CacheStatusAgeExceeded",status="ok"} 64
storage_compactions_total{engine_id="x",level="1",node_id="0",reason="",status="ok"} 12
storage_compactions_total{engine_id="x",level="2",node_id="0",reason="",status="ok"} 3
storage_compactions_total{engine_id="x",level="3",node_id="0",reason="",status="ok"} 1
storage_compactions_total{engine_id="x",level="full",node_id="0",reason="",status="ok"} 1
storage_compactions_total{engine_id="x",level="snapshot",node_id="0",reason="CacheStatus(4)",status="ok"} 12
storage_compactions_total{engine_id="x",level="snapshot",node_id="0",reason="CacheStatusAgeExceeded",status="ok"} 64
storage_compactions_total{engine_id="x",level="1",node_id="0",reason="",status="ok"} 12