It is possible that when we go to ban a peer, there is already an unbanned message in the queue. It could lead to the case that we ban and immediately unban a peer leaving us in a state where a should-be banned peer is unbanned.
If this banned peer connects to us in this faulty state, we currently do not attempt to re-ban it. This PR does correct this also, so if we do see this error, it will now self-correct (although we shouldn't see the error in the first place).
I have also incremented the severity of not supporting protocols as I see peers ultimately get banned in a few steps and it seems to make sense to just ban them outright, rather than have them linger.
311e69db65