Locking by namespace in cleanUpRange may lead to orphan leaks.

The next flow will result on an orphan leak:

1. A rename was ongoing from collA ---> collB, which copies range deletion docs from collA to collB and keeps the collA ones
2. Step-down happened
3. Step-up happened, so range deletions were resumed
4. The resubmit wrongly happens by namespace rather than collection UUID
5. As namespace collA is not found, that range deletion docs are deleted filtering by UUID+range, so range deletion docs from collB won't be processed.