Assign unnesting level to the last history level

Surprise unnesting ~ is no fun.

sdn.cpp

@@ -2297,9 +2297,6 @@ fun load_config () {
 		else if (tokens.front () == "history")
 			load_history_level (tokens);
 	}
-
-	// FIXME: we don't reset unnest_depth when the last history level
-	//   doesn't match the start directory.
 }
 
 fun save_config () {
@@ -2387,6 +2384,9 @@ int main (int argc, char *argv[]) {
 	load_colors ();
 	load_cmdline (argc, argv);
 	g.start_dir = g.cwd = initial_cwd ();
+	// XXX: We might want to store this within history levels.
+	if (g.levels.empty () || g.levels.back ().path != g.cwd)
+		g.unnest_depth = 0;
 	reload (false);
 	pop_levels (g.cwd);
 	update ();