Multisite: Remove restriction of minimum site name length in `wpmu_validate_blog_signup()`.

It is sometimes desirable to support shorter site names than 4 characters, therefore that restriction should be removed. It is still possible to manually enforce it by using the `wpmu_validate_blog_signup` filter.

As a result of this change, another `is_super_admin()` call gets removed which affects the ongoing efforts of working on a network-wide role system.

Props milindmore22.
Fixes #39676. See #37616.

Built from https://develop.svn.wordpress.org/trunk@40295


git-svn-id: http://core.svn.wordpress.org/trunk@40202 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/ms-functions.php

@@ -576,9 +576,6 @@ function wpmu_validate_blog_signup( $blogname, $blog_title, $user = '' ) {
 	if ( in_array( $blogname, $illegal_names ) )
 		$errors->add('blogname',  __( 'That name is not allowed.' ) );
 
-	if ( strlen( $blogname ) < 4 && !is_super_admin() )
-		$errors->add('blogname',  __( 'Site name must be at least 4 characters.' ) );
-
 	// do not allow users to create a blog that conflicts with a page on the main blog.
 	if ( !is_subdomain_install() && $wpdb->get_var( $wpdb->prepare( "SELECT post_name FROM " . $wpdb->get_blog_prefix( $current_network->site_id ) . "posts WHERE post_type = 'page' AND post_name = %s", $blogname ) ) )
 		$errors->add( 'blogname', __( 'Sorry, you may not use that site name.' ) );

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-40294';
+$wp_version = '4.8-alpha-40295';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.