revoke() cancelled the original tx and built the self-spend using the wallet's
active account, but the locked inputs belong to the account that created the
contract. Revoking while a different account was active would fail to find and
cancel the original tx and would recover funds into the wrong account.
- derive the account from the locked input's root_key_id; use it for cancel_tx
and as the self-spend's src_acct_name.
- test: revoke a contract while a different account is active.
Addresses PR #754 review (revoke.rs).
jwinterm
502d2ae336