MILAN, Italy - Tenor Roberto Alagna marched off the stage at La Scala when the audience booed him during the second performance of Franco Zeffirelli's "Aida." He was replaced seconds later by his understudy, who rushed on wearing jeans. "I do not deserve this kind of reception," Alagna told La Repubblica newspaper after his early exit from Saturday night's performance. [Snip] Thursday night's opening of Zeffirelli's "Aida" was a much-anticipated event, with Italian Premier Romano Prodi and German Chancellor Angela Merkel among the many prominent figures in attendance. [Snip] "In many years at La Scala I had never seen anything...