firmware_ECThermal: Fix a wrong exception type

BUG=chrome-os-partner:11714
TEST=none

Change-Id: I84b13cc6e585a301c677fc47d542b0358c626245
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/37319
diff --git a/server/site_tests/firmware_ECThermal/firmware_ECThermal.py b/server/site_tests/firmware_ECThermal/firmware_ECThermal.py
index 29fda7c..45eeed4 100644
--- a/server/site_tests/firmware_ECThermal/firmware_ECThermal.py
+++ b/server/site_tests/firmware_ECThermal/firmware_ECThermal.py
@@ -139,7 +139,7 @@
         super(firmware_ECThermal, self).setup()
         try:
             self.faft_client.run_shell_command('stop temp_metrics')
-        except ChromeOSInterfaceError:
+        except xmlrpclib.Fault:
             self._has_temp_metrics = False
         else:
             logging.info('Stopped temp_metrics')
@@ -191,7 +191,7 @@
           Temperature reading in degree C.
 
         Raises:
-          ChromeOSInterfaceError: Raised when we fail to read temperature.
+          xmlrpclib.Fault: Raised when we fail to read temperature.
           error.TestError: Raised if ectool doesn't behave as we expected.
         """
         assert sensor_id < self._num_temp_sensor