LONDON (Reuters) - Rapper Jay-Z will return to the London Olympics site this summer where he performed at the 2012 Paralympics as the sporting complex takes on a new life as the Queen Elizabeth Olympic Park. Justin Timberlake and Jay-Z were named on Tuesday by live music promoter Live Nation Entertainment as headline acts for the Wireless Festival on July 12 and July 13. Other acts will include Snoop Dogg, John Legend, Frank Ocean, Emeli Sande, Rita Ora, and DJ Calvin Harris. ...