Add missing newline at end of tools/BUILD

Change-Id: Iac096fc8292682165369c400a36668718b09ff1a
diff --git a/tools/BUILD b/tools/BUILD
index 1fa2160..cc10083 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -1 +1 @@
-# Empty file - bazel treat directories with BUILD file as a package
\ No newline at end of file
+# Empty file - bazel treat directories with BUILD file as a package