auto_updater: Apply cold reboot for AU

Try to reset EC for post StatefulUpdate check to see if Ethernet
dongle probing could be more robust during AU.

BUG=chromium:768542
TEST=python -u ~/trunk/src/platform/dev/cros_update.py -d DUT_IP
-b eve-release/R64-*.0.0 --static_dir
/mnt/host/source/devserver/static/ --force_update --clobber_stateful

Change-Id: I7eb80dee46bdb9b4f3933f819f862cf8bbab06de
Signed-off-by: Chung-yih Wang <cywang@google.com>
Reviewed-on: https://chromium-review.googlesource.com/770636
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Xixuan Wu <xixuan@chromium.org>
diff --git a/scripts/deploy_chrome_unittest.py b/scripts/deploy_chrome_unittest.py
index 7a8f82c..257811a 100644
--- a/scripts/deploy_chrome_unittest.py
+++ b/scripts/deploy_chrome_unittest.py
@@ -161,7 +161,7 @@
   def testDisableRootfsVerificationFailure(self):
     """Test failure to disable rootfs verification."""
     #pylint: disable=unused-argument
-    def RaiseRunCommandError(timeout_sec=None):
+    def RaiseRunCommandError(timeout_sec=None, cold_reboot=False):
       raise cros_build_lib.RunCommandError('Mock RunCommandError', 0)
     self.remote_reboot_mock.side_effect = RaiseRunCommandError
     self.assertRaises(cros_build_lib.RunCommandError,