Remove the pre-populate from harvard course group ref field.

#6661 

We had two vsites: john an obama. Both with the harvard courses app enabled. The settings are:
john: department - Classics, school - faculty of arts and sceince
obama: department - economics, school - faculty of arts and science
When you click on the import courses in john you get all the courses that is being imported, no matter if the course match the app settings. That happens because the group ref field pre-populate was on and did his magic - grouped the created node to the current group.

Another thing is that classic is not belong to the faculty of arts and science school but Harvard Extension School. 

What need to be cover:
* [x] Upgrade path
* [ ] More checking.