session: refactor listen logic

Make app-listener the handle for app listens. Consequently transport and
local listen sessions are now associated to the app-listener.

Change-Id: I9397a26d42cccb100970b6b4794c15bac2e11465
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c
index bbfee57..1adefab 100644
--- a/src/vnet/udp/udp_input.c
+++ b/src/vnet/udp/udp_input.c
@@ -207,7 +207,7 @@
 		  child0->c_rmt_port = udp0->src_port;
 		  child0->c_is_ip4 = is_ip4;
 
-		  if (stream_session_accept (&child0->connection,
+		  if (session_stream_accept (&child0->connection,
 					     tc0->s_index, 1))
 		    {
 		      error0 = UDP_ERROR_CREATE_SESSION;