Bad file descriptor - Bad file descriptor (Errno::EBADF) from monitoring agent

5.1.1

Are these benign? It's coming from the agent that is used by monitoring. It's showing up at the DEBUG level. Is this something the end user have to worry about? There's not a way for me to disable the monitoring agent to isolate this further.

```
[2016-12-27T00:02:14,483][DEBUG][logstash.agent ] Starting puma
[2016-12-27T00:02:14,486][DEBUG][logstash.agent ] Trying to start WebServer {:port=>9600}
[2016-12-27T00:02:14,488][DEBUG][logstash.api.service ] [api-service] start
[2016-12-27T00:02:14,521][INFO ][logstash.agent ] Successfully started Logstash API endpoint {:port=>9600}
[2016-12-27T00:02:14,552][DEBUG][logstash.agent ] Error in reactor loop escaped: Bad file descriptor - Bad file descriptor (Errno::EBADF)
[2016-12-27T00:02:14,553][DEBUG][logstash.agent ] ["org/jruby/RubyIO.java:3705:in `select'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/puma-2.16.0-java/lib/puma/reactor.rb:29:in `run_internal'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/puma-2.16.0-java/lib/puma/reactor.rb:138:in `run_in_thread'"]
[2016-12-27T00:02:14,553][DEBUG][logstash.agent ] Error in reactor loop escaped: Bad file descriptor - Bad file descriptor (Errno::EBADF)
[2016-12-27T00:02:14,554][DEBUG][logstash.agent ] ["org/jruby/RubyIO.java:3705:in `select'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/puma-2.16.0-java/lib/puma/reactor.rb:29:in `run_internal'", "/usr/share/logstash/vendor/bundle/jruby/1.9/gems/puma-2.16.0-java/lib/puma/reactor.rb:138:in `run_in_thread'"]
```