Fixing comment for JetDeltaRValueMapProducer

The comment for the file JetDeltaRValueMapProducer.cc is completely copied (wrongly) from another module.
I fixed it to have the correct comment for posterity and to avoid confusion.

(As if anyone but my future self will ever read this file). 

http://xkcd.com/1421/

Automatically ported from CMSSW_7_2_X #5353