Re: fix side-effect in get_qual_for_list()

Hi Ashutosh,

Thanks for catching this. For now this isn't a problem since
> generate_partition_qual() is crafting PartitionBoundInfo which it
> doesn't use anywhere else. But if the function gets used where the
> PartitionBoundSpec is being used somewhere else as well.

Yes, this behavior currently does not affect adversely, but I think this
function is quite useful for future enhancements and should be fixed.

While you are
> at it, can we use castNode() in place of
> PartitionBoundSpec *spec = (PartitionBoundSpec *) bound; Or do you
> think it should be done separately?
>

I have made this change at couple of places applicable.

PFA.

Regards,
Jeevan Ladhe