message: Fix a minor bug where the wrong value was being logged.
diff: @@ -1166,7 +1166,7 @@ class CollectiveAllReduce(CrossDeviceOps):
  if not context.executing_eagerly() and replica_id == 0:
  logging.info(
  "Collective all_reduce IndexedSlices: %d all_reduces, num_devices ="
  - "%d, group_size = %d, implementation = %s", len(dense_values),
  + "%d, group_size = %d, implementation = %s", len(sparse_values),
  len(self._launchers), self._group_size, implementation)
  for indexed_slice in sparse_values:
  