[autotest] Removed copy of unittest library.

All tests still pass with the standard unittest library.

BUG=None
TEST=Executed utils/unittest_suite.py locally

Change-Id: I86f7e2884282bca0fcb240fe2f70c4adb71f8ddf
Reviewed-on: https://chromium-review.googlesource.com/357330
Commit-Ready: Justin Giorgi <jgiorgi@google.com>
Tested-by: Justin Giorgi <jgiorgi@google.com>
Reviewed-by: Richard Barnette <jrbarnette@google.com>
Reviewed-by: Simran Basi <sbasi@chromium.org>
diff --git a/scheduler/rdb_integration_tests.py b/scheduler/rdb_integration_tests.py
index 5113a6c..0312a05 100755
--- a/scheduler/rdb_integration_tests.py
+++ b/scheduler/rdb_integration_tests.py
@@ -5,11 +5,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 import collections
+import unittest
 
 import common
-
 from autotest_lib.client.common_lib import host_queue_entry_states
-from autotest_lib.client.common_lib.test_utils import unittest
 from autotest_lib.frontend import setup_django_environment
 from autotest_lib.frontend.afe import frontend_test_utils
 from autotest_lib.frontend.afe import models