title: How can I rewrite one value in the settings for the test
body: <p>How can I rewrite 'user': '5/minute' on 'user': '2/day' in the settings for the test</p>
  
  <pre><code>REST_FRAMEWORK = {
      'DEFAULT_THROTTLE_RATES': {
           'user': '5/minute'
      }
  }
  </code></pre>
  
  <p>How can i do this with @override_settings or mb with context manage? 
  I need to apply this only in one test, I can not rewrite the whole dictionary</p>
  
  <pre><code>def test_mytest(self):
      value = settings.REST_FRAMEWORK
      value['DEFAULT_THROTTLE_RATES'] = {'user':'2/day'}
  
      data1 = {}
      data2 = {}
      data3 = {}
  
  with self.settings(REST_FRAMEWORK=value):
      resp1 = self.client.post(self.url, data1, format='json')
      resp2 = self.client.post(self.url, data1, format='json')
      resp3 = self.client.post(self.url, data1, format='json')
  
  assert resp3.status_code == 429, resp3.data
  </code></pre>
  
  <p>But no have 429 error, although the value has changed</p>