When a primary defers creation of the _id index, the secondary still creates the _id index when applying the oplog entry for the collection creation. This results in inconsistent indexes between primary and secondary. We should remove occurrences of deferred _id index creation:
– chunk migration
– cloner (all occurrences in that file)
– renameCollection
– repairDatabase (mmapv1)

We need not change initial sync or the oplog buffer collection, since those collection creations are not replicated.