[1.7.x] Fixed #22710 -- Documented aggregation behavior for empty QuerySets.
[1.7.x] Fixed #22710 -- Documented aggregation behavior for empty QuerySets.

Thanks matklad for the report.

Backport of 7c6e96ec1f from master

jyotsna1820/django,jyotsna1820/django,jyotsna1820/django,oscaro/django,oscaro/django,jyotsna1820/django,oscaro/django,oscaro/django