[cmake-developers] Version number updates for 2.8.12

[David Cole]

We should (maybe I will if I get time to spend on it) write a test that 
executes something like this command:

    $ git grep -E "[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9].*cmPolicies"
    Source/cmPolicies.cxx:    2,8,11,20130516, cmPolicies::WARN);
    Source/cmPolicies.cxx:    2,8,11,20130516, cmPolicies::WARN);
    Source/cmPolicies.cxx:    2,8,11,20130724, cmPolicies::WARN);

And make sure the results are empty-ish... Then if somebody does this 
later on, it will be a test failure.


D