face: enable congestion marking by default on supported faces

refs #4465

Change-Id: Id545f83763f1ba27ba0d770fd4398948d6f20acf
diff --git a/daemon/face/face-system.hpp b/daemon/face/face-system.hpp
index 1a49fce..87c0fc3 100644
--- a/daemon/face/face-system.hpp
+++ b/daemon/face/face-system.hpp
@@ -84,7 +84,7 @@
    */
   struct GeneralConfig
   {
-    bool wantCongestionMarking = false;
+    bool wantCongestionMarking = true;
   };
 
   /** \brief context for processing a config section in ProtocolFactory