mgmt+face: allow MTU of datagram faces to be overridden

refs #4005

Change-Id: I01d98b88cdee41b633f6fb9a5600088efe8de749
diff --git a/daemon/face/udp-channel.cpp b/daemon/face/udp-channel.cpp
index b87e697..eb4337f 100644
--- a/daemon/face/udp-channel.cpp
+++ b/daemon/face/udp-channel.cpp
@@ -160,6 +160,8 @@
   socket.connect(remoteEndpoint);
 
   GenericLinkService::Options options;
+  options.allowFragmentation = true;
+  options.allowReassembly = true;
   options.reliabilityOptions.isEnabled = params.wantLpReliability;
 
   if (boost::logic::indeterminate(params.wantCongestionMarking)) {
@@ -178,7 +180,8 @@
   }
 
   auto linkService = make_unique<GenericLinkService>(options);
-  auto transport = make_unique<UnicastUdpTransport>(std::move(socket), params.persistency, m_idleFaceTimeout);
+  auto transport = make_unique<UnicastUdpTransport>(std::move(socket), params.persistency,
+                                                    m_idleFaceTimeout, params.mtu);
   auto face = make_shared<Face>(std::move(linkService), std::move(transport));
 
   m_channelFaces[remoteEndpoint] = face;