AU: Minor fixes to get it to do full update on real device

- Link w/ gtest only for unittests.

- filesystem_copier_action: always send install plan on the output pipe
  on success, even if no copy was performed.

- omaha_response_handler: properly choose install partition based on
  new GPT partition spec.

- More useful logging to match memento_updater (which update URL is
  used, dump of the request/response for the update check).

- Fixed a bug where I wasn't bonding the proper actions together in update_attempter.

BUG=None
TEST=attached unittests/did full update on Eee PC

Review URL: http://codereview.chromium.org/2044001
diff --git a/update_check_action.cc b/update_check_action.cc
index 106400b..57e82eb 100644
--- a/update_check_action.cc
+++ b/update_check_action.cc
@@ -107,6 +107,8 @@
   http_fetcher_->set_delegate(this);
   string request_post(FormatRequest(params_));
   http_fetcher_->SetPostData(request_post.data(), request_post.size());
+  LOG(INFO) << "Checking for update at " << params_.update_url;
+  LOG(INFO) << "Request: " << request_post;
   http_fetcher_->BeginTransfer(params_.update_url);
 }
 
@@ -190,8 +192,12 @@
 void UpdateCheckAction::TransferComplete(HttpFetcher *fetcher,
                                          bool successful) {
   ScopedActionCompleter completer(processor_, this);
-  if (!successful)
+  LOG(INFO) << "Update check response: " << string(response_buffer_.begin(),
+                                                   response_buffer_.end());
+  if (!successful) {
+    LOG(ERROR) << "Update check network transfer failed.";
     return;
+  }
   if (!HasOutputPipe()) {
     // Just set success to whether or not the http transfer succeeded,
     // which must be true at this point in the code.