stop using nativefs for file location

nativefs doesn't work on iOS since LÖVE v11.5, so I should stop using it
at least on forks for mobile devices.

I still use it in a couple of cases:
* on a file DELETE request from the driver
* when trying to write modifications from the driver to the original
  location

0177-has_local_modifications

@@ -1,3 +1,3 @@
 has_local_modifications = function(filename)
-	return nativefs.getInfo(App.save_dir..Directory..filename)
+	return love.filesystem.getRealDirectory(Directory..filename) == love.filesystem.getSaveDirectory()
 end

0195-can_be_unstashed

@@ -2,5 +2,5 @@ can_be_unstashed = function(pane)
 	if not pane.is_stash then return end
 	assert(pane.filename)
 	local filename = unstash_filename(pane.filename)
-	return not nativefs.getInfo(App.save_dir..Directory..filename)
+	return not has_local_modifications(filename)
 end