update bok choy db caches
update bok choy db caches
Merge branch 'mvo/update_bok_choy_db_caches' of https://github.com/edx/edx-platform into mvo/update_bok_choy_db_caches
Merge pull request #4636 from edx/mvo/update_bok_choy_db_caches

update bok choy db caches