title: Ember data, how to get dispose of models in isError state
body: <p>If I try and persist a model to a backend API and it fails, the model record is still in the store.</p>
  
  <p>E.g.</p>
  
  <pre><code>todo.one 'becameError', (result)  -&gt;
    #result.get('isError') == true
  </code></pre>
  
  <p>If I do a call to App.Todo.all(), the todo that failed is in the store and will appear in the app unless I filter out objects that have an isError state.</p>
  
  <p>Is there a way I can dispose of the object when it is in this state?</p>
  
  <p>I cannot call deleteRecord because there is an assertion stopping it being called for models that are an in an isError state.</p>