[autotest] update compile_gwt_clients to log error on failure.

Currently we log info on a failure, update this to log error.

BUG=chromium:384661
TEST=Compile_gwt_client still works.

Change-Id: I29ea194c474ad5f83629ec89a0a4cc2b338cb607
Reviewed-on: https://chromium-review.googlesource.com/204550
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Commit-Queue: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
diff --git a/utils/compile_gwt_clients.py b/utils/compile_gwt_clients.py
index 9f83a1b..22478cf 100755
--- a/utils/compile_gwt_clients.py
+++ b/utils/compile_gwt_clients.py
@@ -112,7 +112,7 @@
                                             project_client)
         return True
     except error.CmdError:
-        logging.info('Error compiling %s, leaving old client', project_client)
+        logging.error('Error compiling %s, leaving old client', project_client)
 
     return False