Failed `get_term_by()` lookups should always return `false`.

Previously, we sometimes returned `null`.

Props charlestonsw, tyxla.
Fixes #33281.
Built from https://develop.svn.wordpress.org/trunk@34246


git-svn-id: http://core.svn.wordpress.org/trunk@34210 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/taxonomy-functions.php

@@ -803,8 +803,9 @@ function get_term_by($field, $value, $taxonomy, $output = OBJECT, $filter = 'raw
 		$field = 'tt.term_taxonomy_id';
 	} else {
 		$term = get_term( (int) $value, $taxonomy, $output, $filter );
-		if ( is_wp_error( $term ) )
+		if ( is_wp_error( $term ) || is_null( $term ) ) {
 			$term = false;
+		}
 		return $term;
 	}
 

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-34245';
+$wp_version = '4.4-alpha-34246';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.