Two DLA Piper partners, including the co-managing partner in Chicago, are leaving the firm.Brendan P. Head and Steven V. Napolitano, who was co-chair of DLA Piper’s U.S. private equity practice, are heading to Kirkland & Ellis LLP, according to a source familiar with the move.A spokesperson for DLA Piper confirmed the departures.“We wish Steve and Brendan all the best and look forward to collaborating with …