By David Shepardson WASHINGTON (Reuters) – Boeing said Wednesday the company would take a new $766 million charge on its 2018 billion contract to build two new U.S. presidential airplanes that faced repeated setbacks. Boeing Chief Executive Dave Calhoun on Wednesday said “critics were right” to slam the planemaker’s deal. Then President Donald Trump secured a promise from Calhoun’s predecessor, Dennis Muilenburg, that the cost of replacing Air Force One would not exceed $4 billion. “We didn’t get enough price,” Calhoun told CNBC saying the company, adding the “biggest mistake” on the Air Force…