Raise 404 while deleting a deleted image

Fixes bug 1171469

Currently the glance v1 api raises a HTTPForbidden when a user tries
to delete an already deleted image. It should be raising a HTTPNotFound.

Change-Id: I79f83782739bf40f3baba293cbc17fe04ca020bb

glance/api/v1/images.py

@@ -838,11 +838,16 @@ def delete(self, req, id):
                                 request=req,
                                 content_type="text/plain")
 
-        if image['status'] == 'deleted' or image['status'] == 'pending_delete':
+        if image['status'] == 'pending_delete':
             msg = (_("Forbidden to delete a %s image.") % image['status'])
             LOG.debug(msg)
             raise HTTPForbidden(explanation=msg, request=req,
                                 content_type="text/plain")
+        elif image['status'] == 'deleted':
+            msg = _("Image %s not found." % id)
+            LOG.debug(msg)
+            raise HTTPNotFound(explanation=msg, request=req,
+                               content_type="text/plain")
 
         if image['location'] and CONF.delayed_delete:
             status = 'pending_delete'

glance/tests/unit/v1/test_api.py

@@ -2494,8 +2494,9 @@ def test_delete_deleted_image(self):
         req = webob.Request.blank("/images/%s" % UUID2)
         req.method = 'DELETE'
         res = req.get_response(self.api)
-        self.assertEquals(res.status_int, webob.exc.HTTPForbidden.code)
-        self.assertTrue('Forbidden to delete a deleted image' in res.body)
+        self.assertEquals(res.status_int, webob.exc.HTTPNotFound.code)
+        msg = "Image %s not found." % UUID2
+        self.assertTrue(msg in res.body)
 
         # Verify the status is still deleted
         req = webob.Request.blank("/images/%s" % UUID2)