allow distributing all_site_admin_account_users around a large cache ring

Change-Id: I89766dbb524436f7f0cddc9b438c6c6a99546fb4
Reviewed-on: https://gerrit.instructure.com/39904
Reviewed-by: Brian Palmer <brianp@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>