tipc: Message rejection rework preparatory changes

This patch defines a few new message header manipulation routines,
and generalizes the usefulness of another, in preparation for upcoming
rework of TIPC's message rejection code.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 0052c07..a5883b1 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -571,7 +571,7 @@
 		assert(tipc_cltr_bcast_nodes.count != 0);
 		bcbuf_set_acks(buf, tipc_cltr_bcast_nodes.count);
 		msg = buf_msg(buf);
-		msg_set_non_seq(msg);
+		msg_set_non_seq(msg, 1);
 		msg_set_mc_netid(msg, tipc_net_id);
 	}