build: prepare v0.18.4.1

[selsta]

A couple smaller bug fixes have accumuluated.

[plowsof]

monero-blockchain-export --data-dir /var/lib/monero/.bitmonero --blocksdat --output-file blockchain.dat --block-stop 3428800
sha256sum blockchain.dat 
007c93e1cea98d3ac2e6f46bb1f82495469292ca90486bc48c57a110ad94d660  blockchain.dat

height="3428800"
difficulty="0x679a68b5c7c3610"
hash="5f15dbe24d4c029d713f8bd46cf7d4f7277da922bbc10220b32d72ea3f9fd3e0"
node=127.0.0.1:18081
REQ=$(curl http://${node}/json_rpc -d '{"jsonrpc":"2.0","id":"0","method":"get_block_header_by_height","params":{"height":'${height}'}}' >
DATA=$(echo $REQ | jq '.result.block_header')
actual_difficulty=$(echo $DATA | jq -r '.wide_cumulative_difficulty' )
actual_hash=$(echo $DATA | jq -r '.hash')
if [ "$actual_hash" != "$hash" ]; then 
        echo "hashes don't match"; exit
fi
if [ "$difficulty" != "$actual_difficulty" ]; then
        echo "difficulty not equal"; exit
fi
echo "OK"

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