Broadway said goodbye last week to two well-regarded but underperforming productions, with both Harmony and Purlie Victorious: A Non-Confederate Romp Through the Cotton Patch posting better-than-usual weekly box office as last-chancers grabbed seats. Harmony, the Barry Manilow-Bruce Sussman musical about the real-life 1920s German singing group the Comedian Harmonists, filled a robust 99% of seats