Fixing names of postgres tox envs in travis config file.
Fixing names of postgres tox envs in travis config file.

fabrique/django-sortedm2m,gradel/django-sortedm2m,gregmuellegger/django-sortedm2m,fabrique/django-sortedm2m,gradel/django-sortedm2m,gregmuellegger/django-sortedm2m,fabrique/django-sortedm2m,gradel/django-sortedm2m,gregmuellegger/django-sortedm2m