Update the cache forward backend for Django 1.11 compatibility.
Review Request #10253 — Created Oct. 21, 2018 and submitted — Latest diff uploaded
Django's caching support had some API changes since Django 1.6, which
broke the cache forwarding backend. This change provides compatibility
with both by trying to determine which API it needs to use and then
Unit tests pass on Django 1.6 and 1.11.