func (c *Cluster) ExitExclusive(f func(*ClusterTx) error) error {
	logger.Debug("Releasing exclusive lock on cluster db")
	defer c.mu.Unlock()
	return c.transaction(f)
}
func (c *Cluster) ExitExclusive(f func(*ClusterTx) error) error {
	logger.Debug("Releasing exclusive lock on cluster db")
	defer c.mu.Unlock()
	return c.transaction(f)
}
// ExitExclusive runs the given transaction and then releases the lock acquired
// with EnterExclusive.