Simplified the logic for a custom date field for the extended query provider.

Simplified the logic for a custom date field for the extended query provider.

Can simply pass in the SortType as it is now a Tridion.ContentDelivery.DynamicContent.Query.MetadataType

Fixing the custom date field sorting order logic - Related to the fix that was made for the fix of Issue-35

https://code.google.com/p/dynamic-delivery-4-tridion/issues/detail?id=35&can=1#makechanges