Remove unused MachineDeployment constants

 This was first added here kubernetes-sigs#143 and it's never been used.

controllers/mdutil/util.go

@@ -42,20 +42,6 @@ const (
 	// DefaultMachineDeploymentUniqueLabelKey is the label applied to Machines
 	// in a MachineDeployment containing the hash of the template.
 	DefaultMachineDeploymentUniqueLabelKey = "machine-template-hash"
-
-	// FailedMSCreateReason is added in a machine deployment when it cannot create a new machine set.
-	FailedMSCreateReason = "MachineSetCreateError"
-	// FoundNewMSReason is added in a machine deployment when it adopts an existing machine set.
-	FoundNewMSReason = "FoundNewMachineSet"
-	// PausedDeployReason is added in a deployment when it is paused. Lack of progress shouldn't be
-	// estimated once a deployment is paused.
-	PausedDeployReason = "DeploymentPaused"
-
-	// MinimumReplicasAvailable is added in a deployment when it has its minimum replicas required available.
-	MinimumReplicasAvailable = "MinimumReplicasAvailable"
-	// MinimumReplicasUnavailable is added in a deployment when it doesn't have the minimum required replicas
-	// available.
-	MinimumReplicasUnavailable = "MinimumReplicasUnavailable"
 )
 
 // MachineSetsByCreationTimestamp sorts a list of MachineSet by creation timestamp, using their names as a tie breaker.