run cached grade distribution query on slave
run cached grade distribution query on slave

Change-Id: Ifa89d05f007cf238bc98091fceeed6d14cd9067e
Reviewed-on: https://gerrit.instructure.com/160874
Reviewed-by: Cody Cutrer <c4fe2b1d90ef8f2548c8aeabfa633434316f0305@instructure.com>
Tested-by: Jenkins
Product-Review: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>
QA-Review: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>

instructure/analytics,instructure/analytics,instructure/analytics