fix const declaration issue

resource-types.go

@@ -17,10 +17,8 @@ type Node struct {
 type InstanceID uint64
 type InstanceType string
 
-const (
-	VM InstanceType = "VM"
-	CT InstanceType = "CT"
-)
+const VM InstanceType = "VM"
+const CT InstanceType = "CT"
 
 type Instance struct {
 	Type     InstanceType         `json:"type"`