permission_broker: fix linter issues

Fixed various issues reported by cpplint.py when run on
src/platform2/permission_broker.

BUG=None
TEST=cpplint.py `find permission_broker/* | grep "\.cc\|\.h"`
     FEATURES=test emerge-link permission_broker

Change-Id: I865cec67f903360b3b66893a2fda0ff3877dc682
Reviewed-on: https://chromium-review.googlesource.com/210598
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Steve Fung <stevefung@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/permission_broker/udev_scopers.h b/permission_broker/udev_scopers.h
index a028ab2..8700140 100644
--- a/permission_broker/udev_scopers.h
+++ b/permission_broker/udev_scopers.h
@@ -29,4 +29,4 @@
 
 }  // namespace permission_broker
 
-#endif  // PERMISSION_BROKER_UDEV_SCOPERS_H_
\ No newline at end of file
+#endif  // PERMISSION_BROKER_UDEV_SCOPERS_H_