title: findRecord Rejects with successful network request
body: <p>I am doing a simple find record. Getting an odd error.</p>
  
  <pre><code>store.findRecord('icon', id) // id = "UUID-ABC"
    .then((result) =&gt; {
      //do stuff
    })
    .catch((e) =&gt; {
      console.log(e)
    })
  </code></pre>
  
  <p>This fires off a network request and returns an object similar to <a href="http://emberjs.com/api/data/classes/DS.RESTAdapter.html#toc_object-root" rel="nofollow">ember docs</a>. As seen in network dev tools:</p>
  
  <pre><code>{
    "icon": {
        "data": "string",
        "id": "UUID-ABC",
        "location": "string"
    }
  }
  </code></pre>
  
  <p>Rejects with EmberError:</p>
  
  <pre><code>"Assertion Failed: Passing classes to store methods has been removed. Please pass a dasherized string instead of undefined"
  </code></pre>
  
  <p>But I don't understand what is undefined. The id is most definitely defined, as seen in the network return. </p>
  
  <p>I'm the using standard DS.RESTAdapter. With very little other changes. I use a few other actions that return an array of icons model, and they work fine.No errors are reported.</p>