learning_python/lesson2/show_arp.txt --- Already sorted

[cascadeth]

The file show_arp.txt (https://github.com/ktbyers/pynet/blob/master/learning_python/lesson2/show_arp.txt) provided for lesson 2 of the Learning Python for Network Engineers course is already sorted by IP address.

If participants in the course are attempting to sort it, they have no validation that the .sort() method works, because the input is the same as the output.