With inconsistent num_segments, the op still runs. only difference is,
the output takes the size of num_segments irrespective of size of segment_ids and data.
for num_segments less than expected output size, the last elements are ignored
for num_segments more than the expected output size, last elements are assigned 
smallest possible value for the specific numeric type.

For example:

        methods.
*   TensorFlow Debugger (tfdbg) CLI: fix an issue in which the TensorBoard
    Debugger Plugin could not handle total source file size exceeding gRPC
    message size limit (4 MB).
*   `tf.contrib`:
    *   `tf.contrib.framework.zero_initializer` supports ResourceVariable.
    *   Adding "constrained_optimization" to tensorflow/contrib.
*   Other: