Clang format discussion

@ben.boeckel I did a build in Windows and it failed at:

...\VTK\Common\Core\vtkWin32OutputWindow.cxx
...VTK\Common\Core\vtkWin32OutputWindow.cxx(351): error C2143: syntax error: missing ';' before 'this'
...\VTK\Common\Core\vtkWin32OutputWindow.cxx(358): error C2143: syntax error: missing ';' before 'this'

I turns out that for some reason I had VTK_LEGACY_REMOVE:BOOL=OFF in the CMakeCache.txt file. Once I set it to ON everything built OK.