title: Select2 createSearchChoice and removing already created choices
body: <p>I am trying to customize select2 and I am overriding createSearchChoice to return an object when the item is not found.</p>
  
  <p>Then <code>.on('select2-selecting',</code> I am taking the newly created choice and converting it to a 'real' object (persisting to the server). However, now the 'temporary' choice that was created does not match the object and so select2 is still showing the search term as an option because I created a new and different object and treated the search choice as a temporary entity.</p>
  
  <p>How can I stop select2 from appending any previously created search choices from the results? (I would ideally like to purge select2 from 'knowing' about the previously created search choice)</p>