Manually add version+logID to STH struct

Will probably make the data set manifest simpler.

cmd_snapshot.go

@@ -63,14 +63,12 @@ func snapshot(opts options) error {
 		if err != nil {
 			return fmt.Errorf("%s: %v", *log.Description, err)
 		}
+		nextSTH.Version = ct.V1
+		nextSTH.LogID = id
 		nextSTHBytes, err := json.Marshal(nextSTH)
 		if err != nil {
 			return fmt.Errorf("%s: %v", *log.Description, err)
 		}
-		//
-		// It's a bit ugly that ct.SignedTreeHead contains fields that
-		// are not populated.  Doesn't cause any prolems here, however.
-		//
 
 		// Bootstrap log if we don't have any STH yet
 		if _, err := os.Stat(sthFile); err != nil {