remove use of remoteGitConfig

Unfortunately one more use remains..

This should be just as fast as the other method. The remote's Git.Repo
has already had its config read, so Annex.new's call to Git.Config.read
is a noop.

Thid commit was sponsored by andrea rota.

Command/Sync.hs

@@ -454,25 +454,27 @@ pushRemote o remote (Just branch, _) = stopUnless (pure (pushOption o) <&&> need
 				showLongNote "(non-fast-forward problems can be solved by setting receive.denyNonFastforwards to false in the remote's git config)"
 				return ok
   where
+	gc = Remote.gitconfig remote
 	needpush
 		| remoteAnnexReadOnly gc = return False
 		| not (remoteAnnexPush gc) = return False
 		| otherwise = anyM (newer remote) [syncBranch branch, Annex.Branch.name]
 	-- Do updateInstead emulation for remotes on eg removable drives
-	-- formatted FAT, where the post-update hook won't run.
-	postpushupdate repo
-		| annexCrippledFileSystem (remoteGitConfig (Remote.gitconfig remote)) =
-			case Git.repoWorkTree repo of
-				Nothing -> return True
-				Just wt -> ifM (Remote.Git.onLocal repo remote needUpdateInsteadEmulation)
-					( liftIO $ do
-						p <- readProgramFile
-						boolSystem' p [Param "post-receive"]
-							(\cp -> cp { cwd = Just wt })
-					, return True
-					)
-		| otherwise = return True
-	gc = Remote.gitconfig remote
+	-- formatted FAT, where the post-receive hook won't run.
+	postpushupdate repo = case Git.repoWorkTree repo of
+		Nothing -> return True
+		Just wt -> ifM needemulation
+			( liftIO $ do
+				p <- readProgramFile
+				boolSystem' p [Param "post-receive"]
+					(\cp -> cp { cwd = Just wt })
+			, return True
+			)
+	  where
+		needemulation = Remote.Git.onLocal repo remote $
+			(annexCrippledFileSystem <$> Annex.getGitConfig)
+				<&&>
+			needUpdateInsteadEmulation			
 
 {- Pushes a regular branch like master to a remote. Also pushes the git-annex
  - branch.