Direct mode .git/annex/objects directories are no longer left writable

Because that allowed writing to symlinks of files that are not present,
which followed the link and put bad content in an object location.

fsck: Fix up .git/annex/object directory permissions.

This commit was sponsored by an anonymous bitcoin donor.

Annex/Direct.hs

@@ -210,11 +210,11 @@ toDirectGen k f = do
   where
   	fromindirect loc = do
 		{- Move content from annex to direct file. -}
-		thawContentDir loc
 		updateInodeCache k loc
 		void $ addAssociatedFile k f
-		thawContent loc
-		replaceFile f $ liftIO . moveFile loc
+		modifyContent loc $ do
+			thawContent loc
+			replaceFile f $ liftIO . moveFile loc
 	fromdirect loc = do
 		replaceFile f $
 			liftIO . void . copyFileExternal loc