While auditing/working on migration stuff, Alexander Popiak caught an error in one of our Democracy migrations on Kusama. There are still some old storage items under Democracy.VoteOf. I opened this motion to kill the storage prefix for this item via a Root call to System pallet.

Anyone can verify the existing storage items by querying Kusama under the prefix: 0xf2794c22e353e9a839f12faab03a911b02a7afbcd5cd4ad2c68bbc63279ae52e

This is equal to xxhash("Democracy") + xxhash("VoteOf") which you can see in the democracy pallet is not used. It was a typo in our migration code that would normally have cleaned this storage up.

 Kill all storage items with a key that starts with the given prefix.

 **NOTE:** We rely on the Root origin to provide us the number of subkeys under
 the prefix we are removing to accurately calculate the weight of this function.

 # <weight>
 - `O(P)` where `P` amount of keys with prefix `prefix`
 - `P` storage deletions.
 - Base Weight: 0.834 * P µs
 - Writes: Number of subkeys + 1
 # </weight>

- Alexander Popiak found an error in the Democracy migrations on Kusama.
- There are old storage items under Democracy.VoteOf that need to be removed.
- A motion has been opened to remove the storage prefix for this item.
- Anyone can verify the existing storage items by querying Kusama using a specific prefix.
- This error was a typo in the migration code that would have been fixed normally.

#72 Clean up `Democracy.VoteOf` storage in Kusama