File cleanup for presumbit hook.

- Fix logging warning.

BUG=chromium:389247
TEST=None

Change-Id: If0a0133346978811e8a48ca023d3f59ddc29d4f5
Reviewed-on: https://chromium-review.googlesource.com/206302
Reviewed-by: Yusuf Mohsinally <mohsinally@chromium.org>
Tested-by: danny chan <dchan@chromium.org>
Commit-Queue: danny chan <dchan@chromium.org>
diff --git a/server/cros/faft/firmware_test.py b/server/cros/faft/firmware_test.py
index 01b0966..eda80be 100644
--- a/server/cros/faft/firmware_test.py
+++ b/server/cros/faft/firmware_test.py
@@ -1131,7 +1131,7 @@
         """
         logging.info("-[FAFT]-[ start wait_for_kernel_up ]---")
         try:
-            logging.info("Installing deps after boot : %s" % install_deps)
+            logging.info("Installing deps after boot : %s", install_deps)
             self.wait_for_client(install_deps=install_deps)
             # Stop update-engine as it may change firmware/kernel.
             self._stop_service('update-engine')