Sensu check modifications.

Allow for both 'config' metadata for a check in addition to 'event' metadata to send with the event to the Sensu handler.

<pre>
  sensu::check { 'namenode_health':
    command => '/etc/sensu/plugins/check_hdfs -w :::namenode_health.threshold:::',
    handlers => ['pagerduty', 'sendgrid'],
    interval => '60',
    standalone => true,
    subscribers => ['namenode'],
  }

  sensu::config { 'namenode_health':
    config => { 'threshold' => '22' },
    event  => { 'sendgrid' => { 'mail_to' => 'myemail@email.com' }, 'runbook' => 'https://wiki/alerts#NameNodeprocessdownalert' }
  }
</pre>