message: Correct an IndexedSlices-related test in replicate_model_fn_test.py.
  I attempted to exercise compute_sum_on_device(IndexedSlices) via the DNNCLassifier test per reviewer's suggestion.  This changelist is way to do it correctly.  I verified that it indeed triggers the required codepath by adding logging and removing compute_sum_on_device(IndexedSlices) support.
diff: @@ -89,11 +89,11 @@ class DNNClassifierIntegrationTest(test_util.TensorFlowTestCase):
  feature_columns = [
  feature_column.numeric_column('x', shape=(input_dimension,)),
  - feature_column.indicator_column(
  + feature_column.embedding_column(
  feature_column.categorical_column_with_vocabulary_list(
  'categories',
  vocabulary_list=np.linspace(
  - 0., len(x_data), len(x_data), dtype=np.int64)))
  + 0., len(x_data), len(x_data), dtype=np.int64)), 1)
  ]
  estimator = dnn.DNNClassifier(
  