face: Implementing new "isOnDemand" flag

This flags replaces isPermanent flag in datagram faces, but with the
reversed logic (isPermanent = !isOnDemand)

Change-Id: I37ba604e5f105ca95a79a08b8cfc3d640df8b412
Refs: #1376
diff --git a/daemon/face/udp-face.hpp b/daemon/face/udp-face.hpp
index 038c7c3..6c1e3a8 100644
--- a/daemon/face/udp-face.hpp
+++ b/daemon/face/udp-face.hpp
@@ -22,7 +22,7 @@
   typedef boost::asio::ip::udp protocol;
 
   UdpFace(const shared_ptr<protocol::socket>& socket,
-          bool isPermanent);
+          bool isOnDemand);
 
   //@todo if needed by other datagramFaces, it could be moved to datagram-face.hpp
   /**