Use $app->enqueueMessage instead of JError and SOME_ERROR_CODE

### Tracker

http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=33865&start=0

### Open Point

Here:
https://github.com/zero-24/joomla-cms/blob/patch-9/libraries/joomla/client/helper.php#L222-229

we use
```php
if (class_exists('JError'))
{
$return = JError::raiseWarning('SOME_ERROR_CODE', JText::_('JLIB_CLIENT_ERROR_HELPER_SETCREDENTIALSFROMREQUEST_FAILED'));
}
else
{
throw new InvalidArgumentException('Invalid user credentials');
}
```

can this replaced by
```php
throw new InvalidArgumentException(JText::_('JLIB_CLIENT_ERROR_HELPER_SETCREDENTIALSFROMREQUEST_FAILED'));
```

Or should we replace the JERROR Statment with
```php
JFactory::getApplication()->enqueueMessage();
```