Low Description
Currently, when renaming or dropping a keyspace, HintedHandoffManager.renameHints() is called to drop and re-insert every hint for that keyspace with the new keyspace name.
This code appears to have been written for a different HintsCF schema, as it drops the row named by the old keyspace name and re-creates all of it's columns under the key of the new keyspace name. This is not the current HintsCF schema. It seems the impact of this is that it doesn't do anything (beyond a pointless index scan for the HintsCF) as the keys will never exist.
It looks safe to remove this code entirely and let the hints simply become invalid. When they're replayed invalid hints are silently dropped, which seems like the best option.