debug log number of unknown wallet records on load
Summary:
This would have saved me some time during wallet debugging, with minimal logging clutter.
Backport of Bitcoin Core PR12888
https://github.com/bitcoin/bitcoin/pull/12888
Test Plan:
- make check-all
- ./src/bitcoind -regtest
- Verify that "Unknown wallet records:" appears in the log file.
Reviewers: Fabien, #bitcoin_abc, deadalnix
Reviewed By: #bitcoin_abc, deadalnix
Differential Revision: https://reviews.bitcoinabc.org/D4079