I've been looking and I can't find that clause. Do you have a link?
History of the Veto
Tracing the veto back to the Roman Republic, Spitzer states that the veto was used by tribunes to protect plebeian interests from those of the patricians. And, as a result of their conquests, the concept of the veto was spread throughout Europe, eventually coming to be one of the last vestiges of power the British monarchs had over the law-making process.
From there the veto made its way to America. But due to the experiences the colonies had had with the veto, they initially made it unavailable to those in power. However, by the time the founders met in Philadelphia, the question was not whether or not to include the veto – or as it was known at the time, the negative – in the Constitution, but whether it should be absolute or qualified.
It should be noted, though, that the founders intended the veto not just as a block to bad legislation, but as a revisionary tool whereby the president and Congress could come to an agreement on a proposed bill.