MINOR: connection: add names for transport and data layers

This makes debugging easier and avoids having to put ugly checks
against certain well-known internal struct pointers.
diff --git a/src/session.c b/src/session.c
index cdf57e3..93fdf52 100644
--- a/src/session.c
+++ b/src/session.c
@@ -41,6 +41,7 @@
 	.send = NULL,
 	.wake = conn_update_session,
 	.init = conn_complete_session,
+	.name = "SESS",
 };
 
 /* Create a a new session and assign it to frontend <fe>, listener <li>,