Return 204 from DELETE /v2/images/<image_id>

Fix bug 995224

The v2 API design and normal RESTful idiom would suggest that a
204 No Content status is more appropriate than 200 OK.

Change-Id: Ic5ae3ffa22eafdec0f780d16cceb8ce45c84c854

glance/api/v2/images.py

@@ -60,7 +60,7 @@ def update(self, req, image_id, image):
 
     def delete(self, req, image_id):
         try:
-            return self.db_api.image_destroy(req.context, image_id)
+            self.db_api.image_destroy(req.context, image_id)
         except exception.NotFound:
             raise webob.exc.HTTPNotFound()
 
@@ -124,6 +124,9 @@ def index(self, response, images):
         }
         response.body = json.dumps(body)
 
+    def delete(self, response, result):
+        response.status_int = 204
+
 
 def create_resource(conf):
     """Images resource factory method"""

glance/tests/functional/v2/test_images.py

@@ -99,7 +99,7 @@ def test_image_lifecycle(self):
         # Deletion should work
         path = self._url('/v2/images/%s' % image_id)
         response = requests.delete(path, headers=self._headers())
-        self.assertEqual(200, response.status_code)
+        self.assertEqual(204, response.status_code)
 
         # This image should be no longer be directly accessible
         path = self._url('/v2/images/%s' % image_id)