pytest: make join_nodes / line_graph wait for updates in both dirs.

This is what fund_channel() does, which is more thorough than what
we were doing.  But since the order of the logs is undefined, we need
to be a little careful.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

contrib/pyln-testing/pyln/testing/utils.py

@@ -1105,9 +1105,29 @@ class NodeFactory(object):
         for src, dst in connections:
             wait_for(lambda: src.channel_state(dst) == 'CHANNELD_NORMAL')
             scid = src.get_channel_scid(dst)
-            src.daemon.wait_for_log(r'Received channel_update for channel {scid}/. now ACTIVE'.format(scid=scid))
             scids.append(scid)
 
+        # We don't want to assume message order here.
+        # Wait for ends:
+        nodes[0].daemon.wait_for_logs([r'update for channel {}/0 now ACTIVE'
+                                       .format(scids[0]),
+                                       r'update for channel {}/1 now ACTIVE'
+                                       .format(scids[0])])
+        nodes[-1].daemon.wait_for_logs([r'update for channel {}/0 now ACTIVE'
+                                        .format(scids[-1]),
+                                        r'update for channel {}/1 now ACTIVE'
+                                        .format(scids[-1])])
+        # Now wait for intermediate nodes:
+        for i, n in enumerate(nodes[1:-1]):
+            n.daemon.wait_for_logs([r'update for channel {}/0 now ACTIVE'
+                                    .format(scids[i]),
+                                    r'update for channel {}/1 now ACTIVE'
+                                    .format(scids[i]),
+                                    r'update for channel {}/0 now ACTIVE'
+                                    .format(scids[i + 1]),
+                                    r'update for channel {}/1 now ACTIVE'
+                                    .format(scids[i + 1])])
+
         if not wait_for_announce:
             return