deal with .git pointer file in Git.CurrentRepo

This fixes the bug.

Note, it's only done when GIT_DIR is set. When it's not set,
Git.Construct already handled it. This is why it was only noticed with this
git submodule command.

This commit was sponsored by Brett Eisenberg on Patreon.

Git/CurrentRepo.hs

@@ -67,15 +67,14 @@ get = do
 	configure (Just d) _ = do
 		absd <- absPath d
 		curr <- getCurrentDirectory
-		r <- Git.Config.read $ newFrom $
-			Local
-				{ gitdir = toRawFilePath absd
-				, worktree = Just (toRawFilePath curr)
-				}
+		loc <- adjustGitDirFile $ Local
+			{ gitdir = toRawFilePath absd
+			, worktree = Just (toRawFilePath curr)
+			}
+		r <- Git.Config.read $ newFrom loc
 		return $ if Git.Config.isBare r
 			then r { location = (location r) { worktree = Nothing } }
 			else r
-
 	configure Nothing Nothing = giveup "Not in a git repository."
 
 	addworktree w r = changelocation r $ Local