Don't show "Link added." in link-add.php if an empty form was submitted. fixes #12262.

git-svn-id: https://develop.svn.wordpress.org/trunk@13960 602fd350-edb4-49c9-b593-d223f7449a82

wp-admin/link.php

@@ -67,9 +67,11 @@ switch ($action) {
 	case 'add' :
 		check_admin_referer('add-bookmark');
 
-		add_link();
+		$redir = wp_get_referer();
+		if ( add_link() )
+			$redir = add_query_arg( 'added', 'true', $redir );
 
-		wp_redirect( wp_get_referer() . '?added=true' );
+		wp_redirect( $redir );
 		exit;
 		break;