Corrected scope of _construct to protected

_construct() is intended to act as a "mock" constructor and not supposed to be accessed outside of the context of $this

Author: dfelton

app/code/Magento/Cron/Model/ResourceModel/Schedule.php

@@ -18,7 +18,7 @@ class Schedule extends \Magento\Framework\Model\ResourceModel\Db\AbstractDb
      *
      * @return void
      */
-    public function _construct()
+    protected function _construct()
     {
         $this->_init('cron_schedule', 'schedule_id');
     }