Fix compile error when USE_CHROME_NETWORK_PROXY is not set.

A recent CL introduced a compile error when USE_CHROME_NETWORK_PROXY is
not set. This patch removes the extra ).

BUG=None
TEST=sudo emerge update_engine
CQ-DEPEND=CL:596802

Change-Id: I79c2af759e829ce14dd6cb7062d29a8882100280
(cherry picked from commit 209e57a848a022fd38fca31a267817fef654d56b)
Reviewed-on: https://chromium-review.googlesource.com/629856
Commit-Ready: Amin Hassani <ahassani@chromium.org>
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
diff --git a/real_system_state.cc b/real_system_state.cc
index 703a175..b6e59cd 100644
--- a/real_system_state.cc
+++ b/real_system_state.cc
@@ -151,7 +151,7 @@
 #if USE_CHROME_NETWORK_PROXY
                           network_proxy_service_proxy_.get()));
 #else
-                          nullptr)));
+                          nullptr));
 #endif  // USE_CHROME_NETWORK_PROXY
 
   // Initialize the UpdateAttempter before the UpdateManager.