when lb tcp in2out flow,
in2out and out2in protocol are not same

Change-Id: I4ce680ad1f088cb079e1f2aeb15ca59225fca0d1
Signed-off-by: ahdj007 <dong.juan1@zte.com.cn>
diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index 24895a0..f009ce4 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -1372,6 +1372,7 @@
       s->outside_address_index = ~0;
       s->in2out = l_key;
       s->out2in = e_key;
+      s->out2in.protocol = l_key.protocol;
       u->nstaticsessions++;
 
       /* Add to lookup tables */