title: jira-python - how do you update the fixVersions field?
body: <p>I'm not sure what I'm doing wrong here, and am hoping someone else has the same problem. I don't get any error, and my json matches what should be correct both on Jira's docs and jira-python questions online. My versions are valid Jira versions. I also have no problem doing this directly through the API, but we are re-writing everything to go through jira-python for cleanliness/ease of use.</p>
  
  <p>This just completely clears the fixVersions field in Jira. </p>
  
  <pre><code>issue=jira.issue("TKT-100")
  issue.update(fields={'fixVersions':[{'add': {'name': 'add_me'}},{'remove': {'name': 'remove_me'}}]})
  </code></pre>
  
  <p>I can add a new version to fixVersions using issue.add_field_value(), but this won't work, because I need to add and remove in one request for the history of the ticket. </p>
  
  <pre><code>issue.add_field_value('fixVersions', {'name': 'add_me'})
  </code></pre>
  
  <p>Any ideas?</p>