The previous change I had for adding an index for search added it in

BaseReviewRequestDetails. While we didn't need it for drafts, I figured

it didn't hurt.
However, it exposed a bug in django-evolution, where, presumably due to

the base class, applying the change to ReviewRequest's signature also

affected ReviewRequestDraft's.
I don't have a fix for that yet in django-evolution, so for now, I'm

splitting that field out and turning indexing on only for

ReviewRequest.summary.

Was able to successfully run an evolution on an older database.