Better detection whether we are on the Network page. Use custom constant to tell us. See #13565, props nacin

We used to load multisite translations each time WP_ALLOW_MULTISITE was defined, but
it could lead to alot of false positives. Generic config files can include to allow
users to updgrade to multisite without further editing the config file.


git-svn-id: http://svn.automattic.com/wordpress/trunk@15064 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/network.php

@@ -10,6 +10,8 @@
  * @subpackage Administration
  */
 
+define( 'WP_NETWORK_ADMIN_PAGE', true );
+
 /** WordPress Administration Bootstrap */
 require_once( './admin.php' );
 

wp-includes/l10n.php

@@ -367,7 +367,7 @@ function load_default_textdomain() {
 
 	load_textdomain( 'default', WP_LANG_DIR . "/$locale.mo" );
 	
-	if ( is_multisite() || ( defined( 'WP_ALLOW_MULTISITE' ) && WP_ALLOW_MULTISITE ) ) {
+	if ( is_multisite() || ( defined( 'WP_NETWORK_ADMIN_PAGE' ) && WP_NETWORK_ADMIN_PAGE ) ) {
 		load_textdomain( 'default', WP_LANG_DIR . "/ms-$locale.mo" );
 	}
 }