display "Recording state in git..." when staging the journal

A bit tricky to avoid printing it twice in a row when there are queued git
commands to run and journal to stage.

Added a generic way to run an action that may output multiple side
messages, with only the first displayed.

Annex/Branch.hs

@@ -330,6 +330,7 @@ setCommitted = void $ do
 {- Stages the journal into the index. -}
 stageJournal :: Annex ()
 stageJournal = do
+	showStoringStateAction
 	fs <- getJournalFiles
 	g <- gitRepo
 	withIndex $ liftIO $ do

Annex/Content.hs

@@ -297,8 +297,8 @@ getKeysPresent = liftIO . traverse (2 :: Int) =<< fromRepo gitAnnexObjectDir
  - especially if performing a short-lived action.
  -}
 saveState :: Bool -> Annex ()
-saveState oneshot = do
-	Annex.Queue.flush False
+saveState oneshot = doSideAction $ do
+	Annex.Queue.flush
 	unless oneshot $
 		ifM alwayscommit
 			( Annex.Branch.commit "update" , Annex.Branch.stage)

Annex/Queue.hs

@@ -26,15 +26,14 @@ add command params files = do
 flushWhenFull :: Annex ()
 flushWhenFull = do
 	q <- get
-	when (Git.Queue.full q) $ flush False
+	when (Git.Queue.full q) flush
 
 {- Runs (and empties) the queue. -}
-flush :: Bool -> Annex ()
-flush silent = do
+flush :: Annex ()
+flush = do
 	q <- get
 	unless (0 == Git.Queue.size q) $ do
-		unless silent $
-			showSideAction "Recording state in git"
+		showStoringStateAction
 		q' <- inRepo $ Git.Queue.flush q
 		store q'