[MEDIUM] make default_backend work in TCP mode too

The default_backend did not work in TCP mode since there was no
header state to assign the backend. This causes much trouble when
configs are created by copy-paste.

The solution was to fix the way the backend is assigned upon accept().
A wrong contimeout assignment was fixed too.
diff --git a/tests/test-retries.cfg b/tests/test-retries.cfg
index bd25e42..588812c 100644
--- a/tests/test-retries.cfg
+++ b/tests/test-retries.cfg
@@ -53,6 +53,23 @@
 	server	dead1 1.1.1.1:80 cookie s1
 	server	good1 127.0.0.1:80 cookie s1
 
+frontend frt_default_tcp
+        bind   :8003
+        mode   tcp
+	option httplog
+	default_backend bck_default_tcp
+
+backend bck_default_tcp
+        mode   tcp
+	option httplog
+	retries 2
+	redispatch
+	balance roundrobin
+	contimeout 1000
+	srvtimeout 25000
+	server	dead1 1.1.1.1:80
+	server	good1 127.0.0.1:80
+
 frontend frt_default
         bind   :8004
         mode   http