Update to 4.1.4 causes cron error

I edited RuleStorage.php and modified:

return $this->database->query('SELECT rid FROM {' . $this->getBaseTable() . '} WHERE `limit` IS NULL')

to:

return $this->database->query('SELECT rid FROM {' . $this->getBaseTable() . '} WHERE "limit" IS NULL')

This appears to have fixed the issue, but not sure how this change might affect MySQL databases.

@tyapchyc is this ready for review?

@mandclu
yes, ready for review
Thanks