By Doina Chiacu WASHINGTON (Reuters) - The White House and Pentagon sought to portray a unified stance on Syria on Friday after reports that a memo from Defense Secretary Chuck Hagel criticized U.S. strategy as fuzzy on Syrian President Bashar al-Assad. White House spokesman Josh Earnest said U.S. strategy against Islamic State in Syria and Iraq was working. He denied Washington was focused on weakening the Islamic militants at the expense of its parallel goal of pushing Assad out of power. ...