buddy: fix UCS add/move/copy buddy use cases
Tested the following buddy list operations:
1. add new buddy to new group
2. add new buddy to existing group
3. move single buddy to new group
4. move single buddy to existing group
5. move buddy with 2 entries to new group
6. move buddy with 2 entries to existing group
7. copy buddy to new group
8. copy buddy to existing group
9. add existing buddy to new group
10. add existing buddy to existing group
11. remove one entry from buddy with 2 entries
12. remove single buddy
13. remove existing group with no buddies
14. remove group containing buddy with 2 entries
15. remove group containing buddy with 1 entry
They all work OK now.