Revert "auto_updater: Apply cold reboot for AU"

This reverts commit aed007c176057a9550d4b511809d68e5d8495015.

Reason for revert: <INSERT REASONING HERE>
break the lab: crbug.com/786167

Original change's description:
> 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>

Bug: chromium:768542
Change-Id: If85e70bd5c7d741e466272a72ad0f1353419aeea
Reviewed-on: https://chromium-review.googlesource.com/775541
Reviewed-by: Xixuan Wu <xixuan@chromium.org>
Tested-by: Shuqian Zhao <shuqianz@chromium.org>
diff --git a/scripts/deploy_chrome_unittest.py b/scripts/deploy_chrome_unittest.py
index 257811a..7a8f82c 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, cold_reboot=False):
+    def RaiseRunCommandError(timeout_sec=None):
       raise cros_build_lib.RunCommandError('Mock RunCommandError', 0)
     self.remote_reboot_mock.side_effect = RaiseRunCommandError
     self.assertRaises(cros_build_lib.RunCommandError,