There is a race we see sometimes under valgrind on Travis which shows
gossipd receiving the node_announce from master before it reads the
channel_announce from channeld, and thus fails. The simplest solution
is to send the channel_announce and channel_update to master as well,
so it can ensure it sends them to gossipd in order
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>