Make flake8 ignore E731 error

Part of the code we copied from neutron is now failing due to
a new flake8 default rule. This changes makes tox and travis
ignore it.

Change-Id: I99a30e0f41e295036f62f8f27e50cd96e77d909d
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>

.travis.yml

@@ -6,5 +6,5 @@ install:
   - pip install flake8 --use-mirrors
   - pip install -q . --use-mirrors
 before_script:
-  - flake8 setup.py akanda
+  - flake8 setup.py akanda --ignore=E123,E133,E226,E241,E242,E731
 script: nosetests -d

tox.ini

@@ -24,3 +24,6 @@ setenv = NOSE_WITH_COVERAGE=1
 
 [testenv:venv]
 commands = {posargs}
+
+[flake8]
+ignore = E123,E133,E226,E241,E242,E731