title: django.utils.timezone.now returns UTC in default TimeField
body: <p>I try to prepopulate a TimeField in django_admin with the following code :</p>
  
  <pre><code>from django.utils import timezone
  
  time_start = models.TimeField('Heure de debut',max_length=20, default=timezone.now)
  </code></pre>
  
  <p>I've installed <strong>pytz</strong> and also correctly set</p>
  
  <pre><code>TIME_ZONE = 'Europe/Brussels'
  USE_TZ = True
  </code></pre>
  
  <p>and the "now" button in admin correctly sets the time if I click on it. However, it initialy shows the time in UTC (two hours before the actual time in my case)</p>
  
  <p>Am I missing something and is there a way to solve this ? I don't want to use <strong>auto_now_add=False</strong> because I want to be able to change this time later...</p>