[django/django] add158: 4 flake8 warning fixes

[GitHub]

Branch: refs/heads/master
Home: https://github.com/django/django
Commit: add1584bfa89cec574491bd42af7039d4869afd3
https://github.com/django/django/commit/add1584bfa89cec574491bd42af7039d4869afd3
Author: Alex Gaynor <alex....@gmail.com>
Date: 2014-03-08 (Sat, 08 Mar 2014)

Changed paths:
M django/db/models/sql/query.py
M tests/admin_checks/models.py
M tests/field_deconstruction/tests.py

Log Message:
-----------
4 flake8 warning fixes