update_engine: fixed warnings from cpplint

Fixed all the cpplint warnings in update engine.

BUG=None
TEST=Unit tests still pass.

Change-Id: I285ae858eec8abe0b26ff203b99a42a200ceb71c
Reviewed-on: https://chromium-review.googlesource.com/204027
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/action_processor_unittest.cc b/action_processor_unittest.cc
index a55f0d3..78968ef 100644
--- a/action_processor_unittest.cc
+++ b/action_processor_unittest.cc
@@ -94,7 +94,7 @@
   bool action_completed_called_;
   ErrorCode action_exit_code_;
 };
-}  // namespace {}
+}  // namespace
 
 TEST(ActionProcessorTest, DelegateTest) {
   ActionProcessorTestAction action;