Adding a copyright notice for a patch is not something that we generally do (and your current mod is implicitly claiming the whole file, which doesn't seem right in any case).  My understanding is that US copyright law says you have the copyright whether there's a notice or not, so you don't have to worry about putting anything in there (even assuming such a small piece of code is copyrightable, which is debatable).  Signing the contributor agreement is enough to grant redistribution rights to the code, regardless, so really nothing needs to be added.