MS: Populate `public` on empty `$current_blog` during subdomain activation.

Activation of a subdomain site is done through that new site's address. This address does not exist in the `wp_blogs` table until activation is complete.

In this case we need to make sure `public` is populated to avoid a PHP notice.

Props uglyrobot.
Fixes #24760.

Built from https://develop.svn.wordpress.org/trunk@35782


git-svn-id: http://core.svn.wordpress.org/trunk@35746 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/ms-settings.php

@@ -135,10 +135,11 @@ if ( !isset( $current_site ) || !isset( $current_blog ) ) {
 		ms_not_installed( $domain, $path );
 	}
 
-	// @todo Investigate when exactly this can occur.
+	// During activation of a new subdomain, the requested site does not yet exist.
 	if ( empty( $current_blog ) && wp_installing() ) {
 		$current_blog = new stdClass;
 		$current_blog->blog_id = $blog_id = 1;
+		$current_blog->public = 1;
 	}
 
 	// No site has been found, bail.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-alpha-35781';
+$wp_version = '4.5-alpha-35782';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.