Multisite: Bump `last_changed` cache on site update and creation

When a site is added, updated, or deleted, the `site_ids` cache for a query will no longer be reliable. Bumping `last_changed` will force a new query for site IDs.

See #35791.

Built from https://develop.svn.wordpress.org/trunk@37618


git-svn-id: http://core.svn.wordpress.org/trunk@37586 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/ms-blogs.php

@@ -465,6 +465,8 @@ function clean_blog_cache( $blog ) {
 	 * @param string  $domain_path_key md5 hash of domain and path.
 	 */
 	do_action( 'clean_site_cache', $blog_id, $blog, $domain_path_key );
+
+	wp_cache_set( 'last_changed', microtime(), 'sites' );
 }
 
 /**

wp-includes/ms-functions.php

@@ -1147,6 +1147,8 @@ function wpmu_create_blog( $domain, $path, $title, $user_id, $meta = array(), $s
 	 */
 	do_action( 'wpmu_new_blog', $blog_id, $user_id, $domain, $path, $site_id, $meta );
 
+	wp_cache_set( 'last_changed', microtime(), 'sites' );
+
 	return $blog_id;
 }
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37617';
+$wp_version = '4.6-alpha-37618';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.