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/omaha_request_prep_action.cc b/omaha_request_prep_action.cc
index 6ee2c24..2b019b3 100644
--- a/omaha_request_prep_action.cc
+++ b/omaha_request_prep_action.cc
@@ -43,7 +43,7 @@
                         version,  // app version (from lsb-release)
                         "en-US",  // lang
                         track,  // track
-                        UpdateCheckParams::kUpdateUrl);
+                        update_url);
 
   CHECK(HasOutputPipe());
   SetOutputObject(out);