Death to Kenny

Core has been identifying itself with release "codename" Kenny since 1.0.0.Final.

IMO it's time for the codename tradition to die; it's not really useful and is just another detail to get wrong to add to the ever growing pile of such details. I'll see if I can make be an empty string. I considered something like "N/A" or even null, but there's string concat code out there that appends the codename to the version, and an empty string may work better with that.

We put this name in our MANIFEST.MF files, so for that I will just use the string "N/A".