Add Elasticsearch shield support

[pabrahamsson]

This pull request will add support for Elasticsearch shield (added in dd-agent 5.8.0)

14:21:15 - INFO - running test
---> syntax:manifests
---> syntax:templates
---> syntax:hiera:yaml
Cloning into 'spec/fixtures/modules/stdlib'...
Cloning into 'spec/fixtures/modules/ruby'...
remote: Counting objects: 48, done.
remote: Compressing objects: 100% (39/39), done.
remote: Total 48 (delta 5), reused 25 (delta 1), pack-reused 0
Receiving objects: 100% (48/48), 25.82 KiB | 0 bytes/s, done.
Resolving deltas: 100% (5/5), done.
Checking connectivity... done.
remote: Counting objects: 458, done.
remote: Compressing objects: 100% (318/318), done.
remote: Total 458 (delta 142), reused 365 (delta 125), pack-reused 0
Receiving objects: 100% (458/458), 209.63 KiB | 0 bytes/s, done.
Resolving deltas: 100% (142/142), done.
Checking connectivity... done.
/Users/pabrahamsson/.rvm/rubies/ruby-2.1.6/bin/ruby -I/Users/pabrahamsson/.rvm/gems/ruby-2.1.6/gems/rspec-core-3.4.4/lib:/Users/pabrahamsson/.rvm/gems/ruby-2.1.6/gems/rspec-support-3.4.1/lib /Users/pabrahamsson/.rvm/gems/ruby-2.1.6/gems/rspec-core-3.4.4/exe/rspec --pattern spec/\{classes,defines,unit,functions,hosts,integration,types\}/\*\*/\*_spec.rb --color
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Pending: (Failures listed here are expected and do not affect your suite's status)

  1) datadog_agent::integrations::apache with tags parameter single value this is currently unimplemented behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_apache_spec.rb:48

  2) datadog_agent::integrations::apache with tags parameter empty values single element array of an empty string undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_apache_spec.rb:74

  3) datadog_agent::integrations::apache with tags parameter empty values single value empty string doubly undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_apache_spec.rb:82

  4) datadog_agent::integrations::docker_daemon with tags parameter empty values single element array of an empty string undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_docker_daemon_spec.rb:58

  5) datadog_agent::integrations::docker_daemon with tags parameter empty values single value empty string doubly undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_docker_daemon_spec.rb:66

  6) datadog_agent::integrations::haproxy with creds set incorrectly functionality not yet implemented
     # No reason given
     # ./spec/classes/datadog_agent_integrations_haproxy_spec.rb:53

  7) datadog_agent::integrations::http_check with headers parameter empty values single element array of an empty string undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_http_check_spec.rb:89

  8) datadog_agent::integrations::http_check with headers parameter empty values single value empty string doubly undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_http_check_spec.rb:97

  9) datadog_agent::integrations::http_check with tags parameter empty values single element array of an empty string undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_http_check_spec.rb:127

  10) datadog_agent::integrations::http_check with tags parameter empty values single value empty string doubly undefined behavior
     # No reason given
     # ./spec/classes/datadog_agent_integrations_http_check_spec.rb:135

  11) datadog_agent::integrations::http_check with contact set this functionality appears to not be functional
     # No reason given
     # ./spec/classes/datadog_agent_integrations_http_check_spec.rb:145


Finished in 36.51 seconds (files took 1.1 seconds to load)
1002 examples, 0 failures, 11 pending


Total resources:   26
Touched resources: 6
Resource coverage: 23.08%
Untouched resources:

  Class[Datadog_agent::Integrations::Apache]
  Class[Datadog_agent::Integrations::Docker_daemon]
  Class[Datadog_agent::Integrations::Elasticsearch]
  Class[Datadog_agent::Integrations::Haproxy]
  Class[Datadog_agent::Integrations::Http_check]
  Class[Datadog_agent::Integrations::Jenkins]
  Class[Datadog_agent::Integrations::Marathon]
  Class[Datadog_agent::Integrations::Mesos_master]
  Class[Datadog_agent::Integrations::Mongo]
  Class[Datadog_agent::Integrations::Mysql]
  Class[Datadog_agent::Integrations::Nginx]
  Class[Datadog_agent::Integrations::Ntp]
  Class[Datadog_agent::Integrations::Postgres]
  Class[Datadog_agent::Integrations::Process]
  Class[Datadog_agent::Integrations::Rabbitmq]
  Class[Datadog_agent::Integrations::Redis]
  Class[Datadog_agent::Integrations::Solr]
  Class[Datadog_agent::Integrations::Tomcat]
  Class[Datadog_agent::Integrations::Varnish]
  Class[Datadog_agent::Integrations::Zk]

[truthbk]

Awesome stuff @pabrahamsson, big thanks for the spec tests, really appreciated. Merging this.