image classification example (/example/gluon): no module named data

[aaronmarkham]

Similar to #2048 and as noted in #5717 - some examples don't work out of the box.
This one does not:
https://github.com/apache/incubator-mxnet/blob/master/example/gluon/image_classification.py

python image_classification.py 
Traceback (most recent call last):
  File "image_classification.py", line 33, in <module>
    from data import (get_cifar10_iterator, get_imagenet_iterator,
ModuleNotFoundError: No module named 'data'

[mxnet-label-bot]

Hey, this is the MXNet Label Bot.
Thank you for submitting the issue! I will try and suggest some labels so that the appropriate MXNet community members can help resolve it.
Here are my recommended labels: Gluon, Example