Fixed #11108 -- added ModelAdmin.delete_model, a hook with which to perform...

Fixed #11108 -- added ModelAdmin.delete_model, a hook with which to perform custom pre-post delete behavior.  Thanks to Florian Apolloner for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@14673 bcc190cf-cafb-0310-a4f2-bffc1f526a37