rolling back mock to see if it helps

requirements.txt

@@ -14,7 +14,7 @@ dogstatsd-python==0.5.6
 kombu==3.0.29
 logilab-astng==0.24.3
 logilab-common==1.1.0
-mock==1.3.0
+mock==1.0.1
 pep8==1.6.2
 pylint==1.4.4
 python-dateutil==2.4.2