WP Mail: If post-by-email functionality is disabled, `wp-mail.php` should return a `403 Forbidden` status code instead if `500 Internal Server Error`.

Props Presskopp, tomdxw.
Fixes #37572.
Built from https://develop.svn.wordpress.org/trunk@38332


git-svn-id: http://core.svn.wordpress.org/trunk@38273 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38331';
+$wp_version = '4.7-alpha-38332';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.

wp-mail.php

@@ -12,7 +12,7 @@ require(dirname(__FILE__) . '/wp-load.php');
 
 /** This filter is documented in wp-admin/options.php */
 if ( ! apply_filters( 'enable_post_by_email_configuration', true ) )
-	wp_die( __( 'This action has been disabled by the administrator.' ) );
+	wp_die( __( 'This action has been disabled by the administrator.' ), 403 );
 
 /**
  * Fires to allow a plugin to do a complete takeover of Post by Email.