(Credit: Bill Cooper) Anticipation was already at fever pitch for this new production of “Fidelio” in London, even before Oliver Mears, Royal Opera Artistic Director, appeared on stage before curtain up, evidently the bearer of bad news. “Please don’t be alarmed,” he reassured: Tenor Jonas Kaufmann only had a cold, would indeed sing, and asked for our indulgence. “We’ve been {…}