in_tcp: in_udp: requires <parse> section but it raises exception ambiguous

[cosmo0920]

Check CONTRIBUTING guideline first and here is the list to help us investigate the problem.

• fluentd or td-agent version.

• td-agent 3.2.1

• Environment information, e.g. OS.
  Debian/GNU Linux Stretch
• Your configuration

• https://github.com/uken/fluent-plugin-elasticsearch/files/2768856/td-agent.txt

• Your problem explanation. If you have an error logs, write it together.

in_tcp plugin requires to specify <parse> section but its error message does not have explicit information due to lack of <parse> section.

ArgumentError: parse: init is specified, but there're parameters without default values:@type
  /home/hhatake/GitHub/fluentd/lib/fluent/config/section.rb:178:in `block in generate'
  /home/hhatake/GitHub/fluentd/lib/fluent/config/section.rb:169:in `each'
  /home/hhatake/GitHub/fluentd/lib/fluent/config/section.rb:169:in `generate'
  /home/hhatake/GitHub/fluentd/lib/fluent/configurable.rb:94:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin/base.rb:57:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin_id.rb:39:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/log.rb:580:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin_helper/event_emitter.rb:73:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin_helper/extract.rb:78:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin_helper/parser.rb:83:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin_helper/server.rb:312:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin/in_tcp.rb:44:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/plugin.rb:164:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/root_agent.rb:282:in `add_source'
  /home/hhatake/GitHub/fluentd/lib/fluent/root_agent.rb:122:in `block in configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/root_agent.rb:118:in `each'
  /home/hhatake/GitHub/fluentd/lib/fluent/root_agent.rb:118:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/engine.rb:131:in `configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/engine.rb:96:in `run_configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/supervisor.rb:795:in `run_configure'
  /home/hhatake/GitHub/fluentd/lib/fluent/supervisor.rb:579:in `dry_run'
  /home/hhatake/GitHub/fluentd/lib/fluent/supervisor.rb:597:in `supervise'
  /home/hhatake/GitHub/fluentd/lib/fluent/supervisor.rb:502:in `run_supervisor'
  /home/hhatake/GitHub/fluentd/lib/fluent/command/fluentd.rb:310:in `<top (required)>'
  /home/hhatake/GitHub/fluentd/bin/fluentd:8:in `require'
  /home/hhatake/GitHub/fluentd/bin/fluentd:8:in `<top (required)>'
  /home/hhatake/GitHub/fluentd/vendor/bundle/ruby/2.4.0/bin/fluentd:22:in `load'
  /home/hhatake/GitHub/fluentd/vendor/bundle/ruby/2.4.0/bin/fluentd:22:in `<top (required)>'

This is originally reported in uken/fluent-plugin-elasticsearch#527.