Fix bug internal client's delete_object logs 499

Internal Client's doest not read body for 404.
So, When internal deleing object that not existed, proxy-server logs
its response code to 499.

In this patch, add a code that drain the reponse body to prevent
unexpected disconnect in proxy-server

Change-Id: I6d170fead798d0d539c69d27a6fa8a2d0123ca99
Closes-Bug: #1835324

swift/common/internal_client.py

@@ -618,7 +618,14 @@ class InternalClient(object):
         """
 
         path = self.make_path(account, container, obj)
-        self.make_request('DELETE', path, (headers or {}), acceptable_statuses)
+        resp = self.make_request('DELETE', path, (headers or {}),
+                                 acceptable_statuses)
+
+        # Drain the response body to prevent unexpected disconnect
+        # in proxy-server
+        with closing_if_possible(resp.app_iter):
+            for iter_body in resp.app_iter:
+                pass
 
     def get_object_metadata(
             self, account, container, obj, metadata_prefix='',

test/unit/common/test_internal_client.py

@@ -1163,28 +1163,17 @@ class TestInternalClient(unittest.TestCase):
         self.assertEqual(1, client.set_metadata_called)
 
     def test_delete_object(self):
-        class InternalClient(internal_client.InternalClient):
-            def __init__(self, test, path):
-                self.test = test
-                self.path = path
-                self.make_request_called = 0
-
-            def make_request(
-                    self, method, path, headers, acceptable_statuses,
-                    body_file=None):
-                self.make_request_called += 1
-                self.test.assertEqual('DELETE', method)
-                self.test.assertEqual(self.path, path)
-                self.test.assertEqual({}, headers)
-                self.test.assertEqual((2, 404), acceptable_statuses)
-                self.test.assertIsNone(body_file)
-
         account, container, obj = path_parts()
-        path = make_path(account, container, obj)
-
-        client = InternalClient(self, path)
+        path = make_path_info(account, container, obj)
+        client, app = get_client_app()
+        app.register('DELETE', path, swob.HTTPNoContent, {})
         client.delete_object(account, container, obj)
-        self.assertEqual(1, client.make_request_called)
+        self.assertEqual(app.unclosed_requests, {})
+        self.assertEqual(1, len(app._calls))
+        app.register('DELETE', path, swob.HTTPNotFound, {})
+        client.delete_object(account, container, obj)
+        self.assertEqual(app.unclosed_requests, {})
+        self.assertEqual(2, len(app._calls))
 
     def test_get_object_metadata(self):
         account, container, obj = path_parts()