[walletdb] Fix syntax error in key parser
[walletdb] Fix syntax error in key parser

Github-Pull: #7381
Rebased-From: fa6d4cc09575de30386bfbc5c8c3858cd7a2f42a

MonetaryUnit/MUE-Src,upgradeadvice/MUE-Src,MonetaryUnit/MUE-Src,MonetaryUnit/MUE-Src,upgradeadvice/MUE-Src,MonetaryUnit/MUE-Src,MonetaryUnit/MUE-Src,upgradeadvice/MUE-Src,upgradeadvice/MUE-Src,upgradeadvice/MUE-Src,MonetaryUnit/MUE-Src,upgradeadvice/MUE-Src