[1.5.x] Fixed #20134 -- Correct list of fields that UserManager requires.
[1.5.x] Fixed #20134 -- Correct list of fields that UserManager requires.

Thanks semenov and pegler.

Backport of da5069f68f from master.

ccn-2m/django,ccn-2m/django,ccn-2m/django,alx-eu/django,bliti/django-nonrel-1.5,imtapps/django-imt-fork,hasadna/django,alx-eu/django,imtapps/django-imt-fork,imtapps/django-imt-fork,hasadna/django,ccn-2m/django,bliti/django-nonrel-1.5,alx-eu/django,bliti/django-nonrel-1.5,hasadna/django,alx-eu/django