[CMake] HowTo specify Site/Buildname for Ctest->CDash submissions

[kent williams]

I think this used to go into DartConfiguration.tcl but we don't use
Dart any more for dashboards.

I have read through the instructions

http://www.vtk.org/Wiki/CDash:Build_Management#Client_Configuration

and it describes how to configure things if you're going to run ctest directly.

What it doesn't explain (and it's not explained anywhere I can find
out) is how if you use CMake to build and CMake to test (i.e. make
Nightly) how to specify the site and build name.

So our builds end up with blank site and a generic build name

http://testing.psychiatry.uiowa.edu/CDash/index.php?project=BRAINS3