Refactor site_power_status, power_strip modules into client/cros.

client/site_tests/power_StatsCPUFreq/power_StatsCPUFreq.py

 # Copyright (c) 2010 The Chromium OS 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 logging, time
 from autotest_lib.client.bin import test
-from autotest_lib.client.common_lib import site_power_status
+from autotest_lib.client.cros import power_status
 
 
 class power_StatsCPUFreq(test.test):
     version = 1
 
 
     def run_once(self, test_time=60):
-        cpufreq_stats = site_power_status.CPUFreqStats()
+        cpufreq_stats = power_status.CPUFreqStats()
 
         # log CPU frequency stats since boot
         current_stats = cpufreq_stats.refresh(incremental=False)
         logging.info('CPUFreq stats since boot:\n %s', current_stats)
 
         # sleep for some time to allow the system to go into idle state
         time.sleep(test_time)
 
         # get updated CPU frequency stats
         current_stats = cpufreq_stats.refresh()
         logging.info('CPUFreq stats in the last %d seconds :\n %s',
                      test_time, current_stats)