Avoid watchdogging "Cache rebuild lock hit: event_islandora_*" stuff.

includes/utilities.inc

@@ -197,12 +197,15 @@ function islandora_invoke_hook_list($hook, array $refinements, array $args) {
     $return = array_merge_recursive($return, $result);
     array_shift($args);
   }
-  if (module_exists('rules') && $event = rules_get_cache("event_$hook")) {
-    $parameters = $event->parameterInfo();
+  if (module_exists('rules')) {
+    $event_info = rules_get_event_info($hook);
+    if (isset($event_info['module'])) {
+      $parameters = $event_info['variables'];
       $rule_args = array_slice($args, 0, count($parameters));
       array_unshift($rule_args, $hook);
       $result = call_user_func_array('rules_invoke_event', $rule_args);
     }
+  }
   return $return;
 }