Clean up extreme verbosity of logs in test harness.

au_test_harness/au_test.py

Index: au_test_harness/au_test.py
diff --git a/au_test_harness/au_test.py b/au_test_harness/au_test.py
index a95fa746d799996cdd863a10669ea9c0b57fc16a..9a7194db4146dd5b4a69c8a4692adb83aa8b09c1 100644
--- a/au_test_harness/au_test.py
+++ b/au_test_harness/au_test.py
@@ -81,11 +81,11 @@ class AUTest(unittest.TestCase):
       self.worker.UpdateUsingPayload(payload)
     except UpdateException as err:
       # Will raise ValueError if expected is not found.
-      if re.search(re.escape(expected_msg), err.stdout, re.MULTILINE):
+      if re.search(re.escape(expected_msg), err.output, re.MULTILINE):
         return
       else:
         cros_lib.Warning("Didn't find '%s' in:" % expected_msg)
-        cros_lib.Warning(err.stdout)
+        cros_lib.Warning(err.output)
 
     self.fail('We managed to update when failure was expected')