`ScanForWalletTransactions()` has the following comment about its return value:

```
 * Returns null if scan was successful. Otherwise, if a complete rescan was not
 * possible (due to pruning or corruption), returns pointer to the most recent
 * block that could not be scanned.
```

This is not strictly true. If `abortrescan` is called, then `ScanForWalletTransactions()` will return `nullptr`, even though the scan wasn't successful to the tip.

This in turn causes a minor bug in `importmulti`, where the call doesn't return the correct error and warning about potentially not finding transactions if `abortrescan` was called.

I think the correct fix is for `ScanForWalletTransactions()` to inform the caller that the rescan was aborted.
}
                int64_t nSmartTime;
                nSmartTime = pwtx->nTimeSmart;
                if (!nSmartTime) {
                    nSmartTime = pwtx->nTimeReceived;
                }
                if (nSmartTime <= latestTolerated) {
                    latestEntry = nSmartTime;
                    if (nSmartTime > latestNow) {
                        latestNow = nSmartTime;
                    }
                    break;
                }
            }
            int64_t blocktime = pindex->GetBlockTime();
            nTimeSmart = std::max(latestEntry, std::min(blocktime, latestNow));
        } else {
            WalletLogPrintf("%s: found %s in block %s not in index\n", __func__, wtx.GetHash().ToString(), wtx.hashBlock.ToString());
        }
    }
    return nTimeSmart;
}
bool CWallet::AddDestData(const CTxDestination &dest, const std::string &key, const std::string &value)
{
    if (boost::get<CNoDestination>(&dest))
        return false;
    mapAddressBook[dest].destdata.insert(std::make_pair(key, value));
    return WalletBatch(*database).WriteDestData(EncodeDestination(dest), key, value);
}
bool CWallet::EraseDestData(const CTxDestination &dest, const std::string &key)