arrange for regional output manager to run when -J is enabled

Commands that want to use it have to run their seek action inside
allowConcurrentOutput. Which seems reasonable; perhaps some future command
will want to support the -J flag but not use regions.

The region state moved from Annex to MessageState. This makes sense
organizationally, and note that some uses of onLocal use a different Annex
state, but pass the MessageState into it, which is what is needed.

Messages/Progress.hs

@@ -65,10 +65,7 @@ metered combinemeterupdate key af a = case keySize key of
 		return r
 #else
 	-- Old progress bar code, not suitable for concurrent output.
-	go _ (ConcurrentOutput _) = do
-		r <- nometer
-		liftIO $ putStrLn $ fromMaybe (key2file key) af
-		return r
+	go _ (ConcurrentOutput _) = nometer
 	go size NormalOutput = do
 		showOutput
 		progress <- liftIO $ newProgress "" size