Subject: syntheticcontroldata clustering example failure due to combiner

r783617 removed the CanopyCombiner and refactored its semantics back
into the reducer. Updated unit tests pass and Synthetic Control with
Canopy produces 6 clusters. Kmeans also runs produces 6 clusters too. I
really don't like doing stuff in close() but see no practical
alternative. Ideas are still welcomed.

Jeff Eastman wrote: