[autotest] Add logging to db backup.

Add some logging to see how long backup takes.

TEST=Run the script
BUG=None

Change-Id: If4f22ddd384b4292354501f3f258c4f8e71222a5
Reviewed-on: https://chromium-review.googlesource.com/274129
Commit-Queue: Fang Deng <fdeng@chromium.org>
Tested-by: Fang Deng <fdeng@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
diff --git a/site_utils/backup_mysql_db.py b/site_utils/backup_mysql_db.py
index a17c7b2..1e4ecc5 100755
--- a/site_utils/backup_mysql_db.py
+++ b/site_utils/backup_mysql_db.py
@@ -269,10 +269,13 @@
     options = parse_options()
     logging_manager.configure_logging(test_importer.TestImporterLoggingConfig(),
                                       verbose=options.verbose)
+    logging.debug('Start db backup: %s', options.type)
     archiver = MySqlArchiver(options.type, options.keep, options.gs_bucket)
     dump_file = archiver.dump()
+    logging.debug('Uploading backup: %s', options.type)
     archiver.upload_to_google_storage(dump_file)
     archiver.cleanup()
+    logging.debug('Db backup completed: %s', options.type)
 
 
 if __name__ == '__main__':