title: knife ssh cloud.public_ipv4 json array trouble
body: <p>Command:</p>
  
  <pre><code>knife ssh name:node-name "some-command" -VV -a cloud.public_ipv4
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>.......
  DEBUG: Chef::HTTP calling Chef::HTTP::JSONToModelOutput#handle_response
  DEBUG: Chef::HTTP calling Chef::HTTP::JSONInput#handle_response
  DEBUG: Adding ["node-ip-address"]
  DEBUG: establishing connection to ["node-ip-address"]:22
  WARNING: Failed to connect to ["node-ip-address"] -- SocketError: getaddrinfo: Name or service not known
  </code></pre>
  
  <p>In GCE you could add several static external IPs to one instance, in that way json output would be like an array: </p>
  
  <pre><code>"public_ipv4": ["10.0.0.1", "10.0.0.2", "...."]
  </code></pre>
  
  <p>In case of only one external ip it should be like this: </p>
  
  <pre><code>"public_ipv4": ["10.0.0.1"]
  </code></pre>
  
  <p>So knife ssh command gettin' public_ipv4 from json as an array with [""]</p>
  
  <p>How to remove that square brackets &amp; quotes to knife ssh connect successfully?</p>
  
  <p>Thx in advance.</p>