Required wallet DB fields do not get persistently added

[johnalotoski]

Context

After creating a wallet using the cardano-wallet-shelley create from-mnemonic $NAME command, each restart of cardano-wallet server shows the following messages in the logs:

[cardano-wallet.wallet-db:Info:4] [$DATETIME] Found existing wallet: $WALLETID
[cardano-wallet.wallet-db:Notice:16] [$DATETIME] wallet table does not contain required field 'passphrase_scheme'. Adding this field with a default value of "EncryptWithPBKDF2".
[cardano-wallet.wallet-db:Notice:16] [$DATETIME] rnd_state_address table does not contain required field 'account_ix'. Adding this field with a default value of 2147483648.

Information	-
Version	2020.6.5 (git revision: 5290acf)
Platform	Linux
Installation	Nix build

Steps to Reproduce

1. Run the cardano-wallet shelley daemon
2. Create a shelley wallet using from-mnemonic.
3. Check the cardano-wallet daemon logs.
4. Restart cardano-wallet daemon.
5. Check the logs for the same wallet id and db messages again.

Wiping the cardano-wallet db and repeating does not resolve.

There appears to be no functional impact to this issue -- at least for what I'm doing.

Expected behavior

The required table values would persist after the first table addition and respective messages in the log would stop after the first time.

[KtorZ]

Moved to: https://jira.iohk.io/browse/ADP-612