[REV] product: rev. 42f5114 needs further review

Incorrect use of stock.move in product module + needs review.

This reverts commit 42f511405a4efe88e3903a4b4040ec9d83e462e2:
"[IMP] When no stock moves, change whatever you want, otherwise no change at all for UoM.  #3440 Enhancement request richard-willowit"