Delete mat*.dat before renaming mail*.dat to it.

Fixes infinite mail loop.

xtrn/lord2/lord2.js

@@ -1857,6 +1857,7 @@ function mail_check(messenger)
 
 	// TODO: Not sure what happens on windows if someone else has the file open...
 	// We likely need a file mutex here.
+	file_delete(f.name)
 	file_rename(fn, f.name);
 	if (!f.open('r'))
 		throw new Error('Unable to open '+f.name);
@@ -1911,6 +1912,7 @@ function mail_check(messenger)
 				lln(l);
 		}
 	}
+	f.close();
 	con_check();
 	more();
 	if (messenger) {