Django 1.4 doesn't have http.request

Many tests fail under Django 1.4 because the http.request.HttpRequest is
directly in the http module there. Just renaming them all to
http.HttpRequest fixes a lot the tests.

Partial-Bug: #1223748
Change-Id: I3262051d49f1f9e6717eac532573383c81075366
Merge "Django 1.4 doesn't have http.request"