Ensure that the `$exclusions` parameter of 'list_terms_exclusions' filter is always a string.

Props fhwebcs.
Fixes #31681.
Built from https://develop.svn.wordpress.org/trunk@31813


git-svn-id: http://core.svn.wordpress.org/trunk@31795 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/taxonomy.php

@@ -1824,6 +1824,8 @@ function get_terms( $taxonomies, $args = '' ) {
 
 	if ( ! empty( $exclusions ) ) {
 		$exclusions = ' AND t.term_id NOT IN (' . implode( ',', array_map( 'intval', $exclusions ) ) . ')';
+	} else {
+		$exclusions = '';
 	}
 
 	/**

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta1-31812';
+$wp_version = '4.2-beta1-31813';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.