Event registration end date should not be allowed to be before registration start date

Added an extra rule for this on CRM/Event/Form/ManageEvent/EventInfo.php at line 460:

$start = CRM_Utils_Date::processDate($values['registration_start_date']);
$end = CRM_Utils_Date::processDate($values['registration_end_date']);
if ($start > 0 && $end > 0 && $end <= $start)

{ $errorMsg['registration_end_date'] = ts('Registration end date should be after Registration start date'); }