url_to_postid() typo fix. Props markjaquith. fixes #1612

git-svn-id: http://svn.automattic.com/wordpress/trunk@2822 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -247,7 +247,7 @@ function url_to_postid($url) {
 			// Substitute the substring matches into the query.
 			eval("\$query = \"$query\";");
 			$query = new WP_Query($query);
-			if ( $query->is_post || $query->is_page )
+			if ( $query->is_single || $query->is_page )
 				return $query->post->ID;
 			else
 				return 0;