By Tim Molloy NEW YORK (TheWrap.com) – Elton John will perform at the Emmy Awards for the first time to honor Liberace in recognition of the pianist's HBO biopic, "Behind the Candelabra." John's performance comes as the Stephen Soderbergh film is nominated for 15 Emmys. It will accompany the previously announced appearances by presenters Michael Douglas and Matt Damon, who are both nominated in Outstanding Lead Actor in a Miniseries or Movie category. John's upcoming album, "The Diving Board," his first studio album in seven years, will be released on September 24, two days after the Emmys. …