Simplify the test for the @python_2_unicode_compatible
Simplify the test for the @python_2_unicode_compatible

In Django 1.9 the decorator from six is used so simplify the test to
just check for a __unicode__ method

spartonia/django-oscar,ka7eh/django-oscar,solarissmoke/django-oscar,okfish/django-oscar,django-oscar/django-oscar,taedori81/django-oscar,eddiep1101/django-oscar,spartonia/django-oscar,john-parton/django-oscar,django-oscar/django-oscar,taedori81/django-oscar,sonofatailor/django-oscar,spartonia/django-oscar,django-oscar/django-oscar,anentropic/django-oscar,ka7eh/django-oscar,itbabu/django-oscar,ka7eh/django-oscar,anentropic/django-oscar,michaelkuty/django-oscar,itbabu/django-oscar,WillisXChen/django-oscar,anentropic/django-oscar,sonofatailor/django-oscar,itbabu/django-oscar,john-parton/django-oscar,sasha0/django-oscar,sonofatailor/django-oscar,ka7eh/django-oscar,eddiep1101/django-oscar,sasha0/django-oscar,john-parton/django-oscar,WillisXChen/django-oscar,WillisXChen/django-oscar,solarissmoke/django-oscar,sasha0/django-oscar,django-oscar/django-oscar,solarissmoke/django-oscar,WillisXChen/django-oscar,okfish/django-oscar,okfish/django-oscar,eddiep1101/django-oscar,anentropic/django-oscar,spartonia/django-oscar,okfish/django-oscar,michaelkuty/django-oscar,michaelkuty/django-oscar,john-parton/django-oscar,sonofatailor/django-oscar,taedori81/django-oscar,solarissmoke/django-oscar,michaelkuty/django-oscar,taedori81/django-oscar,eddiep1101/django-oscar,WillisXChen/django-oscar,itbabu/django-oscar,WillisXChen/django-oscar,sasha0/django-oscar