Fix wkhtmltox for Travis
Fix wkhtmltox for Travis

fankcoder/django-wkhtmltopdf,tclancy/django-wkhtmltopdf,fankcoder/django-wkhtmltopdf,denisbalyko/django-wkhtmltopdf,halfnibble/django-wkhtmltopdf,incuna/django-wkhtmltopdf,halfnibble/django-wkhtmltopdf,incuna/django-wkhtmltopdf,powderflask/django-wkhtmltopdf,unrealsolver/django-wkhtmltopdf,powderflask/django-wkhtmltopdf,denisbalyko/django-wkhtmltopdf,unrealsolver/django-wkhtmltopdf,tclancy/django-wkhtmltopdf