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/filesystem_copier_action.cc b/filesystem_copier_action.cc
index 4bfde99..23d3b0e 100644
--- a/filesystem_copier_action.cc
+++ b/filesystem_copier_action.cc
@@ -34,7 +34,7 @@
 
 namespace {
 const off_t kCopyFileBufferSize = 128 * 1024;
-}  // namespace {}
+}  // namespace
 
 FilesystemCopierAction::FilesystemCopierAction(
     SystemState* system_state,