AU: Many minor cleanup changes

src/platform/update_engine/omaha_request_prep_action.h

Index: src/platform/update_engine/omaha_request_prep_action.h
diff --git a/src/platform/update_engine/omaha_request_prep_action.h b/src/platform/update_engine/omaha_request_prep_action.h
index cb82a9f3065b97e337239f612e8b1210b7bc1f9f..d6030f5069b0e1307ff70a111f85b3f2d36fd90a 100644
--- a/src/platform/update_engine/omaha_request_prep_action.h
+++ b/src/platform/update_engine/omaha_request_prep_action.h
@@ -54,7 +54,8 @@ class OmahaRequestPrepAction : public Action<OmahaRequestPrepAction> {
   // Fetches the value for a given key from
   // /mnt/stateful_partition/etc/lsb-release if possible. Failing that,
   // it looks for the key in /etc/lsb-release .
-  std::string GetLsbValue(const std::string& key) const;
+  std::string GetLsbValue(const std::string& key,
+                          const std::string& default_value) const;
 
   // Gets the machine type (e.g. "i686")
   std::string GetMachineType() const;