Comment 1 for bug 1890629

Below is a branch that uses the ancestor tree when searching for events related to the opt-in settings for the org. units that allow patron self-registration:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/dyrcona/lp1890629

It works in my limited testing with CWMARS data.