Fix some simple Python 3 issues with management commands.

Review Request #10322 — Created Nov. 14, 2018 and submitted — Latest diff uploaded

Information

Django Evolution
master
7541d8f...

Reviewers

The management commands still don't have any real Python 3 support.
While this change doesn't guarantee any support, it does fix some
low-hanging fruit involving calls to unicode and raw_input that only
worked with Python 2. These have been updated to make use of six for
cross-version compatibility.

Ran the commands on Python 2 and verified that they're showing help
output and prompting for input.