Revert "Put secrets in another file."

This reverts commit 47afc2ad8c.

inc/instance-config.secret.php.EXAMPLE

@@ -1,24 +0,0 @@
-<?php
-
-/*
-*  Instance Configuration Secrets
-*  ------------------------------
-*  Put secrets here to avoid accidentally leaking them in commits.
-*
-*/
-
-/*
- * Database configuration
- */
-
-$config['db']['server'] = 'localhost';
-$config['db']['database'] = 'lainchan';
-$config['db']['prefix'] = '';
-$config['db']['user'] = 'lainchan';
-$config['db']['password'] = '';
-
-/*
- * Salt
- */
-$config['secure_trip_salt'] = '';
-$config['cookies']['salt'] = '';