For actions, switch bool success into an exit code.

This way we can signal specific error conditions and then
send appropriate events to Omaha from the UpdateAttempter.

BUG=560
TEST=unit tests, gmerged and looked at logs

Review URL: http://codereview.chromium.org/3022008
diff --git a/action_unittest.cc b/action_unittest.cc
index 8dd9edd..8bb94ca 100644
--- a/action_unittest.cc
+++ b/action_unittest.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -32,7 +32,7 @@
   void PerformAction() {}
   void CompleteAction() {
     ASSERT_TRUE(processor());
-    processor()->ActionComplete(this, true);
+    processor()->ActionComplete(this, kActionCodeSuccess);
   }
   string Type() const { return "ActionTestAction"; }
 };