Reconnecting task errors don't identify the worker

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In a bot that uses slack-ruby-bot you get:

W, [2019-04-25T01:42:09.948060 #220]  WARN -- <Async::Task:0x28a05a0 connected to #<Addrinfo: 18.207.50.150:443 TCP (cerberus-xxxx.lb.slack-msgs.com)> running>: The operation has been cancelled!
I, [2019-04-25T01:42:10.101832 #220]  INFO -- : Successfully connected team XYZ (TXYZ) to https://xyz.slack.com.

The first error doesn't say that this team that has disconnected is XYZ.

The code on hello is https://github.com/slack-ruby/slack-ruby-bot/blob/1708693843487f1c1f97765d0d7ebbda1ef34d24/lib/slack-ruby-bot/hooks/hello.rb#L12, we need an event on disconnect to log.