make version of ts_mon compatible with appengine

infra_libs/test/instrumented_requests_test.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import datetime
 import unittest
 
-from infra_libs import http_metrics
+from infra_libs.ts_mon.common import http_metrics
 from infra_libs import instrumented_requests
 
 import requests
 import mock
 
 
 class InstrumentedRequestsTest(unittest.TestCase):
   def setUp(self):
     super(InstrumentedRequestsTest, self).setUp()
     http_metrics._reset_for_testing()
@@ skipping 78 matching lines @@
         '_instrumented_test', 'foo', 'http://example.com',
         hooks={'foo': lambda: 42})
 
     self.assertTrue(f.called)
     self.assertEquals(('http://example.com',), f.call_args[0])
     self.assertIn('hooks', f.call_args[1])
     self.assertIn('response', f.call_args[1]['hooks'])
     self.assertIn('foo', f.call_args[1]['hooks'])
     self.assertTrue(hasattr(f.call_args[1]['hooks']['response'], '__call__'))
     self.assertEquals(42, f.call_args[1]['hooks']['foo']())