pkg-generic: remove unused NAMEVER

Commit 5538e476 (from 2013!) removed the use of the NAMEVER variable in
.stamp_patched, but it was still defined. So remove the definition now.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>