BUG/MEDIUM: peers: fix wrong message id on stick table updates acknowledgement.

The table definition message id was used instead of the update acknowledgement id.

This bug causes a malformated message and a protocol error and breaks the
connection.

After that, the updates remain unacknowledged.
diff --git a/src/peers.c b/src/peers.c
index 1f19fac..b4f6b97 100644
--- a/src/peers.c
+++ b/src/peers.c
@@ -429,7 +429,7 @@
 
 	/*  prepare message header */
 	msg[0] = PEER_MSG_CLASS_STICKTABLE;
-	msg[1] = PEER_MSG_STKT_DEFINE;
+	msg[1] = PEER_MSG_STKT_ACK;
 	cursor = &msg[2];
 	intencode(datalen, &cursor);