[Cmake] Mailing List address (again)

[Brad King]

Hello,

A list member pointed out to me privately that we should use the
domain name of this project without the "www." prefix for the mailing
list.  The web server is already aliased to the proper address, so
we've decided to take the suggestion.

The preferred mailing address for this list is no longer either of the
following

  cmake at www . cmake . org
  cmake at public . kitware . com

but is now

  cmake at cmake . org

Mail will now be delivered from the new address.  Please update your
mail filters accordingly.  Sorry to change this again so soon.

-Brad