Dont treat a timer tick as no_connection_possible and log
In testing, due to other patches, I managed to flood the send queue
with messages and cause us not to be able to send pings, thus
getting a peer disconnected for ping timeout. To my surprise, this
also force-closed all of my channels with that peeer.
Obviously a ping timeout does not indicate that no future connection
with said peer will be possible, and we shouldn't be force-closing
channels as a result.
This also logs when a peer is disconnected to ping timeout to make
debug easier.