Make UpdateAttempter own debugd_proxy.

It's the only class using this proxy.

Test: mma
Bug: 28800946

Change-Id: I1a98b417f213db5d47de451390367ca4975db4b0
diff --git a/fake_system_state.cc b/fake_system_state.cc
index 49ba058..d51f775 100644
--- a/fake_system_state.cc
+++ b/fake_system_state.cc
@@ -21,7 +21,7 @@
 // Mock the SystemStateInterface so that we could lie that
 // OOBE is completed even when there's no such marker file, etc.
 FakeSystemState::FakeSystemState()
-    : mock_update_attempter_(this, nullptr, nullptr, nullptr),
+    : mock_update_attempter_(this, nullptr, nullptr),
       mock_request_params_(this),
       fake_update_manager_(&fake_clock_),
       clock_(&fake_clock_),