By Nate Raymond BOSTON (Reuters) -A former University of Southern California water polo coach was convicted on Friday on charges he accepted more than $200,000 in bribes to help children get into the school as fake athletic recruits in the latest trial to result from the U.S. college admissions scandal. A federal jury in Boston found Jovan Vavic, 60, guilty on all three charges he faced following an investigation into a nationwide fraud and bribery scheme that ensnared celebrities, corporate executives and coaches at elite universities. His lawyers had argued that Vavic never lied or taken a b…