Add note on django version to run unit tests
Add note on django version to run unit tests

Bug: skia:
Change-Id: Ibcd78540da8a934d214991cab6afba3a12ec179a
Reviewed-on: https://skia-review.googlesource.com/29885
Reviewed-by: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Commit-Queue: Ravi Mistry <9fa2e7438b8cb730f96b74865492597170561628@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot