title: Overriding the delete function of BaseInlineFormset
body: <p>I am looking at doing a soft delete on a record. If 'Website' is not a foreign key (say, for example 'RetailerRatingGroup') then it should be deleted as normal. However, it is the foreign key of another object, I want to cancel the deletion and instead change the Website.active property to false. 
  Can anyone point me in the right direction as to how I might go about that. </p>
  
  <pre><code>class Website(models.Model):
      retailer = models.ForeignKey('Retailer', on_delete=models.PROTECT)
      url = models.URLField()
      short_name = models.CharField(max_length=15)
      active = models.BooleanField(default=True)
  
  class RetailerRatingGroup(models.Model):
      retailer = models.ForeignKey(Retailer, on_delete=models.PROTECT)
      channel_productcat = models.ForeignKey('ChannelProductcatGroup', on_delete=models.PROTECT)
      website = models.ForeignKey(Website, blank=True, null=True, on_delete=models.PROTECT)
      current_rating = models.ForeignKey('Rating', default=None, blank=True, null=True, on_delete=models.SET_DEFAULT)
  </code></pre>