Fix wp_clear_scheduled_hook() so that it function prototype matches the other cron functions.

Include backwards compatibility code so that plugins that used the old way still work.
Fixes #10468.

git-svn-id: http://svn.automattic.com/wordpress/trunk@12462 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/cron.php

@@ -130,9 +130,12 @@ function wp_unschedule_event( $timestamp, $hook, $args = array() ) {
  * @since 2.1.0
  *
  * @param string $hook Action hook, the execution of which will be unscheduled.
- * @param mixed $args,... Optional. Event arguments.
+ * @param array $args Optional. Arguments that were to be pass to the hook's callback function.
  */
-function wp_clear_scheduled_hook( $hook ) {
+function wp_clear_scheduled_hook( $hook, $args = array() ) {
+	// Backward compatibility
+	// Previously this function took the arguments as discrete vars rather than an array like the rest of the API
+	if ( !is_array($args) )
 		$args = array_slice( func_get_args(), 1 );
 
 	while ( $timestamp = wp_next_scheduled( $hook, $args ) )