face: delete deprecated FaceSystem constructor

Change-Id: I54d623f1432428c2c3516a00f66dfe3f847bbc2c
Refs: #3377, #4021
diff --git a/daemon/mgmt/face-manager.hpp b/daemon/mgmt/face-manager.hpp
index bee95a3..e50b858 100644
--- a/daemon/mgmt/face-manager.hpp
+++ b/daemon/mgmt/face-manager.hpp
@@ -120,9 +120,11 @@
   void
   connectFaceStateChangeSignal(const Face& face);
 
-PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+private:
   FaceSystem& m_faceSystem;
   FaceTable& m_faceTable;
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
   std::map<FaceId, signal::ScopedConnection> m_faceStateChangeConn;
 
 private: