Homicides in New York City are down below 400 so far in 2012, a big drop from 493 through the same period last year, but Ray Kelly would like everyone to know that his department is doing even better than it looks. Four old murders, including the 1979 disappearance of Etan Patz, were reclassified this year as homicides and count toward the annual total, the NYPD commissioner explained, as do older injuries that resulted in death this year, a practical “bookkeeping matter” that doesn’t reflect the safety of the city today. Depending on how we do for the rest of December, the city could log its fewest murders since 1960.