Index: src/wp-includes/load.php
===================================================================
--- src/wp-includes/load.php	(revision 34880)
+++ src/wp-includes/load.php	(working copy)
@@ -165,7 +165,7 @@
  * @global int $upgrading the unix timestamp marking when upgrading WordPress began.
  */
 function wp_maintenance() {
-	if ( ! file_exists( ABSPATH . '.maintenance' ) || wp_installing() )
+	if ( ! file_exists( ABSPATH . '.maintenance' ) || defined( 'WP_INSTALLING' ) )
 		return;
 
 	global $upgrading;
@@ -475,12 +475,12 @@
  */
 function wp_not_installed() {
 	if ( is_multisite() ) {
-		if ( ! is_blog_installed() && ! wp_installing() ) {
+		if ( ! is_blog_installed() && ! defined( 'WP_INSTALLING' ) ) {
 			nocache_headers();
 
 			wp_die( __( 'The site you have requested is not installed properly. Please contact the system administrator.' ) );
 		}
-	} elseif ( ! is_blog_installed() && ! wp_installing() ) {
+	} elseif ( ! is_blog_installed() && ! defined( 'WP_INSTALLING' ) ) {
 		nocache_headers();
 
 		require( ABSPATH . WPINC . '/kses.php' );
@@ -539,7 +539,7 @@
 function wp_get_active_and_valid_plugins() {
 	$plugins = array();
 	$active_plugins = (array) get_option( 'active_plugins', array() );
-	if ( empty( $active_plugins ) || wp_installing() )
+	if ( empty( $active_plugins ) || defined( 'WP_INSTALLING' ) )
 		return $plugins;
 
 	$network_plugins = is_multisite() ? wp_get_active_network_plugins() : false;