PCT-637: Query Analytics does not handle MySQL Restart

http://tools-ci.percona.com/job/percona-agent-branch/28/console
With buffer 1, instead of `default` do `case := time.After(1*time.Second):` and if that case happens, then log an error because this should never block.  If it does, then the listener has died, locked up, etc., something bad enough to make it stop listening.