AU: Try delta updates first, then full updates

src/platform/update_engine/postinstall_runner_action.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "update_engine/postinstall_runner_action.h"
 #include <sys/mount.h>
 #include <stdlib.h>
 #include "update_engine/utils.h"
 
 namespace chromeos_update_engine {
 
 using std::string;
 
 namespace {
-const string kMountPath(utils::kStatefulPartition + "/au_destination");
+const string kMountPath(string(utils::kStatefulPartition) + "/au_destination");
 const string kPostinstallScript("/postinst");
 }
 
 void PostinstallRunnerAction::PerformAction() {
   CHECK(HasInputObject());
   const string install_device = GetInputObject();
 
   int rc = mount(install_device.c_str(), kMountPath.c_str(), "ext3", 0, NULL);
   if (rc < 0) {
     LOG(ERROR) << "Unable to mount destination device " << install_device
@@ skipping 14 matching lines @@
     // non-fatal
     LOG(ERROR) << "Unable to umount destination device";
   }
   if (success && HasOutputPipe()) {
     SetOutputObject(install_device);
   }
   processor_->ActionComplete(this, success);
 }
 
 }  // namespace chromeos_update_engine