finish fixing removeLink on windows

9cb250f7be got the ones in RawFilePath,
but there were others that used the one from unix-compat, which fails at
runtime on windows. To avoid this,
import System.PosixCompat.Files hiding removeLink

This commit was sponsored by Ethan Aubin.

Remote/Directory.hs

@@ -301,10 +301,10 @@ retrieveExportM d _k loc dest p =
 
 removeExportM :: RawFilePath -> Key -> ExportLocation -> Annex ()
 removeExportM d _k loc = liftIO $ do
-	removeWhenExistsWith removeLink src
+	removeWhenExistsWith R.removeLink src
 	removeExportLocation d loc
   where
-	src = fromRawFilePath $ exportPath d loc
+	src = exportPath d loc
 
 checkPresentExportM :: RawFilePath -> Key -> ExportLocation -> Annex Bool
 checkPresentExportM d _k loc =