Fix import of some autotest cros modules, make them callable outside of autotest runtime.

Change-Id: Ibd2e309e02490ed9c580c046663e287911f2bc75

BUG=None
TEST=run_remote_test bvt

Review URL: http://codereview.chromium.org/6626031
diff --git a/client/cros/dns_server.py b/client/cros/dns_server.py
index 8ce2ad0..7deb4ea 100644
--- a/client/cros/dns_server.py
+++ b/client/cros/dns_server.py
@@ -2,7 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import logging, threading, time, utils
+import logging, threading, time
+from autotest_lib.client.bin import utils
 
 class LocalDns(object):
     """a wrapper around miniFakeDns that handles managing running the server