Merge pull request #1052 from LukeOl/missed_cronjobs_history_cleanup_fix

Fix for missed cronjobs history cleanup

app/code/Magento/Cron/Model/Observer.php

@@ -353,7 +353,8 @@ class Observer
         $now = time();
         /** @var Schedule $record */
         foreach ($history as $record) {
-            if (strtotime($record->getExecutedAt()) < $now - $historyLifetimes[$record->getStatus()]) {
+            $checkTime = strtotime($record->getExecutedAt() ? $record->getExecutedAt() : $record->getScheduledAt());
+            if ($checkTime < $now - $historyLifetimes[$record->getStatus()]) {
                 $record->delete();
             }
         }