Update buildifier script

Remove the function-docstring warning check. Only check the regular
format error in the bazel files (the typical bazel usage)

Change-Id: Ia4f6212cf27644394ed4687741c5e3b441a0257a

preupload-hooks/run_buildifier.sh

diff --git a/preupload-hooks/run_buildifier.sh b/preupload-hooks/run_buildifier.sh
index 56f9003..6051ba5 100755
--- a/preupload-hooks/run_buildifier.sh
+++ b/preupload-hooks/run_buildifier.sh
@@ -65,8 +65,6 @@
 # Run buildifier formatter and linter. The diff is compared with git-diff.
 "${CACHE}/buildifier/buildifier" "${files[@]}" || (echo "buildifier error" && exit 1)
 
-"${CACHE}/buildifier/buildifier" -lint=warn -warnings=-module-docstring,-function-docstring "${files[@]}"
-
 git diff --exit-code || (echo """
 Please amend the commit with: