face: enable congestion marking by default on supported faces

refs #4465

Change-Id: Id545f83763f1ba27ba0d770fd4398948d6f20acf
diff --git a/daemon/face/face-system.cpp b/daemon/face/face-system.cpp
index 6430796..ebdce9c 100644
--- a/daemon/face/face-system.cpp
+++ b/daemon/face/face-system.cpp
@@ -95,7 +95,6 @@
     for (const auto& pair : *generalSection) {
       const std::string& key = pair.first;
       if (key == "enable_congestion_marking") {
-        // false by default
         context.generalConfig.wantCongestionMarking = ConfigFile::parseYesNo(pair, "face_system.general");
       }
       else {
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