swift tableview的分割线不能到头

1，设置tableview的separatorInset， layoutMargins

if(myTableView.respondsToSelector("setSeparatorInset:")) {
            myTableView.separatorInset = UIEdgeInsetsMake(0, 0, 0, 0)
        }
        if(myTableView.respondsToSelector("setLayoutMargins:")) {
            myTableView.layoutMargins = UIEdgeInsetsMake(0, 0, 0, 0)
        }

2，设置cell的separatorInset， layoutMargins

    func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
        if(cell.respondsToSelector("setSeparatorInset:")) {
            cell.separatorInset = UIEdgeInsetsMake(0, 0, 0, 0)
        }
        if(cell.respondsToSelector("setLayoutMargins:")) {
            cell.layoutMargins = UIEdgeInsetsMake(0, 0, 0, 0)
        }
    }