Another dependency fix.

SConstruct

Index: SConstruct
diff --git a/SConstruct b/SConstruct
index 71e9788bcc6661e753bb0521962d5fc24af6ff67..09e27b0419c2c06933c638d28a1da9dc95e1ee91 100644
--- a/SConstruct
+++ b/SConstruct
@@ -178,6 +178,7 @@ env['BUILDERS']['GlibMarshal'] = glib_marshal_builder
 #     which is built as a side effect of building update_metadata.pb.cc
 env.Depends('bzip_extent_writer_unittest.cc', 'update_metadata.pb.cc');
 env.Depends('bzip_extent_writer.cc', 'update_metadata.pb.cc');
+env.Depends('cycle_breaker.cc', 'update_metadata.pb.cc');
 
 #   Some files indirectly include marshal.glibmarshal.h
 #     which is built as a side effect of the .c file
@@ -186,7 +187,7 @@ env.Depends('dbus_service.cc', 'marshal.glibmarshal.c');
 #   Some files indirectly include update_engine.dbusserver.h
 #     which is built as a side effect of the dbusclient.h file
 env.Depends('mock_http_fetcher.cc', 'update_engine.dbusclient.h');
-env.Depends('main.cc', 'update_engine.dbusserver.h');
+env.Depends('main.cc', 'update_engine.dbusclient.h');
 
 # Fix issue with scons not passing pkg-config vars through the environment.
 for key in Split('PKG_CONFIG_LIBDIR PKG_CONFIG_PATH'):