dl: verify didn't finish

[AskAlexSharov]

1. Seems --verify flag doesn't do anything:

go run ./cmd/downloader  --seedbox --verify --datadir=/erigon-data/ --chain=bor-mainnet

2. i did rm -rf downloader to trigger verify. it worked well, but then stuck at

INFO[08-26|05:03:41.525] [snapshots] Downloading                  progress="27.12% 1.1TB/4.1TB" downloading=24 download=0B/s upload=0B/s peers=1 conns=1 files=3280 alloc=3.6GB sys=7.4GB

restart helped - progress grow to 60% then suck. next restart helped - progress finished

[AskAlexSharov]

same as #11670

[dvovk]

Should be fixed with #11874