* Version 1.7 can't create wp-config.php when installing with WordPress 4.0

	When install process notices that there's no wp-config.php, it tries to
	create one from wp-config-sample.php. During that time, WordPress unsets
	global $wpdb and calls require_wp_db() function.
	That function newly instantiates wpdb class. SQLite Integration has no
	way of intercepting that process.

