Support git's core.sharedRepository configuration

This is incomplete, it does not honor it yet for hash directories
and other annex bookkeeping files. Some of that is not needed for a bare
repo; some of it may be.

Command/Fsck.hs

@@ -166,10 +166,9 @@ verifyLocationLog key desc = do
 	-- Since we're checking that a key's file is present, throw
 	-- in a permission fixup here too.
 	when present $ do
-		f <- inRepo $ gitAnnexLocation key
-		liftIO $ do
-			preventWrite f
-			preventWrite (parentDir f)
+		file <- inRepo $ gitAnnexLocation key
+		freezeContent file
+		freezeContentDir file
 
 	u <- getUUID
 	verifyLocationLog' key desc present u (logChange key u)

Command/Unannex.hs

@@ -10,7 +10,6 @@ module Command.Unannex where
 import Common.Annex
 import Command
 import qualified Annex
-import Utility.FileMode
 import Logs.Location
 import Annex.Content
 import qualified Git.Command
@@ -51,9 +50,8 @@ cleanup file key = do
 		( do
 			-- fast mode: hard link to content in annex
 			src <- inRepo $ gitAnnexLocation key
-			liftIO $ do
-				createLink src file
-				allowWrite file
+			liftIO $ createLink src file
+			thawContent file
 		, do
 			fromAnnex key file
 			logStatus key InfoMissing

Command/Unlock.hs

@@ -46,6 +46,6 @@ perform dest key = do
 			liftIO $ do
 				removeFile dest
 				moveFile tmpdest dest
-				allowWrite dest
+			thawContent dest
 			next $ return True
                 else error "copy failed!"