Make Logstash complain if attempting to use batch_count (redis input plugin) with a single-threaded filter plugin.

I tried to use a configuration today by accident that included the redis input plugin's batch_count setting as well as a zeromq filter in the same configuration.

Zeromq requires that it be single threaded and I know that logstash can detect that but for some reason after setting the batch_count in the redis input plugin, it starts up and doesn't complain at all.

I finally found it when I went into the configuration file and noticed the setting after I determined it wasn't ingesting from it's input.

I think it would be helpful if logstash complained about this setting either through configtest or otherwise.