more OsPath conversion

About 1/10th done with this I think.

Config/Files.hs

@@ -16,7 +16,7 @@ import Utility.Exception
 {- ~/.config/git-annex/file -}
 userConfigFile :: OsPath -> IO OsPath
 userConfigFile file = do
-	dir <- toOsPath <$> userConfigDir
+	dir <- userConfigDir
 	return $ dir </> literalOsPath "git-annex" </> file
 
 autoStartFile :: IO OsPath

Config/Files/AutoStart.hs

@@ -30,8 +30,7 @@ modifyAutoStartFile func = do
 	when (dirs' /= dirs) $ do
 		f <- autoStartFile
 		createDirectoryIfMissing True (parentDir f)
-		viaTmp (writeFile . fromRawFilePath . fromOsPath)
-			(toOsPath f)
+		viaTmp (writeFile . fromRawFilePath . fromOsPath) f
 			(unlines (map fromOsPath dirs'))
 
 {- Adds a directory to the autostart file. If the directory is already