Republican presidential candidate Trump gestures and declares "You're fired!" at a rally in ManchesterBy Emily Flitter and Jennifer Ablan NEW YORK (Reuters) – Donald Trump had to do a bit of damage control on Thursday after repeatedly dropping Carl Icahn’s name in a campaign speech and then saying most good business negotiators were “vicious, horrible, miserable human beings.” Icahn, the billionaire investor, called Trump, the real estate mogul turned U.S. presidential candidate, to ask for an explanation after Trump made the comments in a speech. After that conversation, Trump told Reuters in a phone interview that he did not mean to include Icahn in his characterization. Trump, who is leading the Republican field in the polls by a wide margin, was telling the audience at a rally in Greenville, South Carolina, that the U.S. needed strong negotiators in key government roles.