During the upgrade to 5.x, question categories are moved to new
mod_qbank module contexts, and any set references using those categories
are updated using `move_question_set_references()`. However, this
function wasn't updating the `cat` arribute of the set reference's
filter condition, leaving it pointing at the original context ID.
This change update `move_question_set_references()` so that when a set
reference is moved (during the 5.x upgrade, or otherwise) the `cat`
parameter will be updated correctly.
For sites that have already gone through the 5.x upgrade, this fix also
adds a CLI script to find and fix incorrect question_set_reference
records. I considered adding this as an upgrade step, but it potentially
has a lot of records to check, and it's redundant if the site is being
upgraded to 5.x with this fix already in place.
Mark Johnson
b5fd7946f0