President Michel Martelly will not perform again as his alter ego, Sweet Micky, after all, an adviser said Thursday. Mr. Martelly, who before his election in April had a long career as a singer known for dressing in drag and disrobing on stage, had said in September he would retake the stage on Dec. 23 to raise $10 million for education. But an adviser said the concert had been postponed indefinitely “due to the holiday season and the complexity of organizing such an event.”