register libnetwork API and UI with docker parent chain

This commit also brings in the ability to specify a default network and its
corresponding driver as daemon flags. This helps in existing clients to
make use of newer networking features provided by libnetwork.

Signed-off-by: Madhu Venugopal <madhu@docker.com>

api/server/server_linux.go

@@ -70,6 +70,7 @@ func (s *Server) newServer(proto, addr string) ([]serverCloser, error) {
 func (s *Server) AcceptConnections(d *daemon.Daemon) {
 	// Tell the init daemon we are accepting requests
 	s.daemon = d
+	s.registerSubRouter()
 	go systemd.SdNotify("READY=1")
 	// close the lock so the listeners start accepting connections
 	select {