Checks if an original file exists for a revision.
This variable checks for a dOriginalName value.
It is possible for a content item to be checked in but to not have an original file (for example, when a Basic workflow has been started but files have not been checked in at the initial contribution step).
Returns TRUE if an original file exists.
Returns FALSE if no original file exists.
Checks for an original file:
<$if HasOriginal and not isNew$>