downloader: don't include completion-rate into download-rate

[AskAlexSharov]

Example start of synced node:

[INFO] [12-09|03:30:33.140] [1/9 OtterSync] Downloading              progress="(1279/1279 files) 61.37% - 1.2TB/1.9TB" rate=60.5GB/s time-left=0hrs:0m total-time=39s download-rate=60.5GB/s completion-rate=60.4GB/s alloc=1.6GB sys=3.2GB

it does re-hash some things: completion-rate > 0
but it including completion-rate into download-rate

also maybe rate is not so useful

[dvovk]

The download represents downloaded bytes and completion shows downloaded and hashed. On restart the torrent-lib does re-hash of some part if download doesn't finished. The rate is a value which shows download or completion rate depending on the current state of the downloader. If files don't downloaded it shows download rate if they downloaded it shows completion rate and status changes from Downloading to Verifying. It was done because on slow machines completion can take some time to finish and it appears to user as a stuck at 100% but in fact the torrent-lib was hashing downloaded files (at some case I remember around 20 min on bor). On faster machines download and completion processing at the same time so download and completion shows the same values. My proposal was to left only rate in logs. I don't remember why we decided to keep download and completion printing.

[AskAlexSharov]

I know what it means - just it feels redundant (not sure if it adds more clarity for user or adds more mess):
downloading=100Kb/s hashing=20kb/s vs rate=120Kb/s downloading=100Kb/s hashing=20kb/s
downloading=0Kb/s hashing=100kb/s vs rate=100Kb/s downloading=0Kb/s hashing=100kb/s
but it's up to you. feel free to close this ticket if it look/feel not useful.

[AskAlexSharov]

as you can see it's confusing: #13250