hold request selection_ou needs fkey

Patch at https://git.evergreen-ils.org/?p=working/Evergreen.git;a=commit;h=a7314d01520a4a4cef75259bc945bb4bce3a24c1

I've found at least one production database that has ahr.selection_ou values that are not present in the actor.org_unit table. (Possibly as a leftover from removal of an old OU).

Consequently, the upgrade script will need to do *something* to catch that case. Perhaps set selection_ou to request_lib?

Galen has a good point and I think that defaulting to request_lib is the safest bet. So I've pushed an update to update ahr selection_ou to request_lib when the selection_ou isn't in actor.org_unit

Thanks, Rogan, for identifying this and fixing it! I've made a few tweaks:

1. Squashing your commits
2. adding the lp number to the commit message
3. Using the NOT VALID / VALIDATE CONSTRAINT pattern to minimize locking on action.hold_request in the upgrade script.
4. Also in the upgrade script, simplifying (at least to my eye) the UPDATE query that adjusts invalid selection_ou -- although your version worked just fine as well, and I could be persuaded either way.

I chose to treat this as a new feature, with the reasoning that it is a new improvement to our database API. As such, with 3.11 frozen for new features, I merged it for inclusion in 3.12.

umm, scratch number 2. Looks like I never actually added the lp number to the commit message. :-)