Add Django 1.11 tox env
Add Django 1.11 tox env

Change-Id: If26325ec260135064e178fa2254ddf7026bbce67

BiznetGIO/horizon,BiznetGIO/horizon,NeCTAR-RC/horizon,yeming233/horizon,openstack/horizon,yeming233/horizon,yeming233/horizon,noironetworks/horizon,ChameleonCloud/horizon,ChameleonCloud/horizon,NeCTAR-RC/horizon,noironetworks/horizon,NeCTAR-RC/horizon,openstack/horizon,ChameleonCloud/horizon,yeming233/horizon,BiznetGIO/horizon,BiznetGIO/horizon,openstack/horizon,openstack/horizon,noironetworks/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,noironetworks/horizon