7104de8 [wallet] Fix leak in CDB constructor (João Barbosa)
Pull request description:
First commit fixes a minor leak.
Second commit improves the constructor in the failure cases.
Tree-SHA512: 5165413d60ed9fc28203c9fe128adbba03a9ea9e9aa3734d9ea2522dafd815ba0fb8b90fd0809dbc06eb3ad360e7764de01dadf653ade3350fe86f6b8f04bc90