Django Migrations Says Database Backend Isn't Available

I was having similar problems upgrading from 1.9.9 to 1.10.1

django.core.exceptions.ImproperlyConfigured: 'django.contrib.gis.db.backends.postgis' isn't an available database backend.
Try using 'django.db.backends.XXX', where XXX is one of:
    'mysql', 'oracle', 'postgresql', 'sqlite3'
Error was: cannot import name 'GDALRaster'

It went away by upgrading the gdal dependency -> brew install --upgrade gdal for me on OSX

Out of ideas, I upgraded Django from 1.7.10 to 1.8.4 and the problem went away. I don't know why this fixed it but it did.