start splitting out readonly values from AnnexState

Values in AnnexRead can be read more efficiently, without MVar overhead.
Only a few things have been moved into there, and the performance
increase so far is not likely to be noticable.

This is groundwork for putting more stuff in there, particularly a value
that indicates if debugging is enabled.

The obvious next step is to change option parsing to not run in the
Annex monad to set values in AnnexState, and instead return a pure value
that gets stored in AnnexRead.

Remote/Git.hs

@@ -750,7 +750,7 @@ repairRemote r a = return $ do
 		ensureInitialized
 		a `finally` stopCoProcesses
 
-data LocalRemoteAnnex = LocalRemoteAnnex Git.Repo (MVar (Maybe Annex.AnnexState))
+data LocalRemoteAnnex = LocalRemoteAnnex Git.Repo (MVar (Maybe (Annex.AnnexState, Annex.AnnexRead)))
 
 {- This can safely be called on a Repo that is not local, but of course
  - onLocal will not work if used with the result. -}
@@ -775,20 +775,20 @@ onLocalRepo repo a = do
 	onLocal' lra a
 
 onLocal' :: LocalRemoteAnnex -> Annex a -> Annex a
-onLocal' (LocalRemoteAnnex repo v) a = liftIO (takeMVar v) >>= \case
+onLocal' (LocalRemoteAnnex repo mv) a = liftIO (takeMVar mv) >>= \case
 	Nothing -> do
-		st <- liftIO $ Annex.new repo
-		go (st, ensureInitialized >> a)
-	Just st -> go (st, a)
+		v <- liftIO $ Annex.new repo
+		go (v, ensureInitialized >> a)
+	Just v -> go (v, a)
   where
-	go (st, a') = do
+	go ((st, rd), a') = do
 		curro <- Annex.getState Annex.output
-		let act = Annex.run (st { Annex.output = curro }) $
+		let act = Annex.run (st { Annex.output = curro }, rd) $
 			a' `finally` stopCoProcesses
-		(ret, st') <- liftIO $ act `onException` cache st
-		liftIO $ cache st'
+		(ret, (st', _rd)) <- liftIO $ act `onException` cache (st, rd)
+		liftIO $ cache (st', rd)
 		return ret
-	cache st = putMVar v (Just st)
+	cache = putMVar mv . Just
 
 {- Faster variant of onLocal.
  -