[1.5.x] Fixed #19887 - Noted when callables may be used in ModelAdmin.fields and ModelAdmin.fieldset.
[1.5.x] Fixed #19887 - Noted when callables may be used in ModelAdmin.fields and ModelAdmin.fieldset.

Thanks Patrick Strasser for the suggestion and Zbigniew Siciarz for the patch.

Backport of 722683f508 from master.

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