Add Host To JMX Metrics

[sethAmazon]

Description of the issue

JMX metrics require having host just like cpu metrics.

Description of changes

Add host as a metric to jmx metrics unless omit_hostname is true

License

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Tests

{
  "agent": {
    "debug": true
  },
    "namespace": "HostnameTest",
    "metrics_collected": {
      "cpu": {
        "resources": [
          "*"
        ],
        "measurement": [
          {"name": "cpu_usage_idle", "rename": "CPU_USAGE_IDLE", "unit": "Percent"},
          {"name": "cpu_usage_nice", "unit": "Percent"},
          "cpu_usage_guest"
        ],
        "totalcpu": false,
        "drop_original_metrics": [ "cpu_usage_guest" ],
        "metrics_collection_interval": 10
      },
      "jmx": [
        {
          "endpoint": "localhost:2020",
          "jvm": []
        }
      ]
    }
  }
}

{
  "agent": {
    "debug": true,
    "omit_empty": true
  },
  "metrics": {
    "append_dimensions": {
      "ImageId": "${aws:ImageId}",
      "InstanceId": "${aws:InstanceId}",
      "InstanceType": "${aws:InstanceType}",
      "AutoScalingGroupName": "${aws:AutoScalingGroupName}"
    },
    "namespace": "HostnameTest",
    "metrics_collected": {
      "cpu": {
        "resources": [
          "*"
        ],
        "measurement": [
          {"name": "cpu_usage_idle", "rename": "CPU_USAGE_IDLE", "unit": "Percent"},
          {"name": "cpu_usage_nice", "unit": "Percent"},
          "cpu_usage_guest"
        ],
        "totalcpu": false,
        "drop_original_metrics": [ "cpu_usage_guest" ],
        "metrics_collection_interval": 10
      },
      "jmx": [
        {
          "endpoint": "localhost:2020",
          "jvm": []
        }
      ]
    }
  }
}

Requirements

Before commit the code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint