rbd: reserveSnap() should cleanup its state in case of a failure

[nixpanic]

reserveSnap() could set certain attributes of rbdSnap, but can fail later on. In case of a failure, attributes set in rbdSnap may not be consistent. The function should cleanup its state in case of a failure (UndoReserveName()), and only change rbdSnap attributes on success.

ceph-csi/internal/rbd/rbd_journal.go

Lines 403 to 421 in d5849a4

	rbdSnap.ReservedID, rbdSnap.RbdSnapName, err = j.ReserveName(
	ctx, rbdSnap.JournalPool, journalPoolID, rbdSnap.Pool, imagePoolID,
	rbdSnap.RequestName, rbdSnap.NamePrefix, rbdVol.RbdImageName, kmsID, rbdSnap.ReservedID, rbdVol.Owner,
	"", encryptionType)
	if err != nil {
	return err
	}
	rbdSnap.VolID, err = util.GenerateVolID(ctx, rbdSnap.Monitors, cr, imagePoolID, rbdSnap.Pool,
	rbdSnap.ClusterID, rbdSnap.ReservedID)
	if err != nil {
	return err
	}
	log.DebugLog(ctx, "generated Volume ID (%s) and image name (%s) for request name (%s)",
	rbdSnap.VolID, rbdSnap.RbdSnapName, rbdSnap.RequestName)
	return nil
	}

Originally posted by @iPraveenParihar in #4502 (comment)