update_engine: Use C++11 range-based for loop when possible.

This cleanup just simplifies the notation of several for loops using
the new range-based syntax.

BUG=None
TEST=`FEATURES=test USE="lang clang" emerge-link update_engine`

Change-Id: I2120a1b1c3fd00e9a02a62abfa8427932080d0f9
Reviewed-on: https://chromium-review.googlesource.com/227897
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/update_attempter.cc b/update_attempter.cc
index 200493d..32c3728 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -673,9 +673,8 @@
   actions_.push_back(shared_ptr<AbstractAction>(update_complete_action));
 
   // Enqueue the actions
-  for (vector<shared_ptr<AbstractAction>>::iterator it = actions_.begin();
-       it != actions_.end(); ++it) {
-    processor_->EnqueueAction(it->get());
+  for (const shared_ptr<AbstractAction>& action : actions_) {
+    processor_->EnqueueAction(action.get());
   }
 }
 
@@ -727,9 +726,8 @@
   BuildPostInstallActions(install_plan_action.get());
 
   // Enqueue the actions
-  for (vector<shared_ptr<AbstractAction>>::iterator it = actions_.begin();
-       it != actions_.end(); ++it) {
-    processor_->EnqueueAction(it->get());
+  for (const shared_ptr<AbstractAction>& action : actions_) {
+    processor_->EnqueueAction(action.get());
   }
 
   // Update the payload state for Rollback.