Update Django 1.6 version in tests
Update Django 1.6 version in tests

pombredanne/django-simple-history,emergence/django-simple-history,treyhunner/django-simple-history,luzfcb/django-simple-history,treyhunner/django-simple-history,luzfcb/django-simple-history,pombredanne/django-simple-history,emergence/django-simple-history