kencc: revert back to "set but not used"

kencc: revert back to "set but not used"

The change to "assignment not used" breaks symmetry with
"used and not set" and removes the reference to the
specific warning mentioned in /sys/doc/comp.ms.

Also, the patch was half-assed as that it left some typos
in like "used an not set", which this change also fixed.