COMP: Windows / ITKv4 - Fix build error "illegal parameter from the moc.exe"

Thanks to Steve Pieper for testing the fix works as expected.

See http://www.na-mic.org/Bug/view.php?id=2884

Fixes #2884

git-svn-id: http://svn.slicer.org/Slicer4/trunk@21644 3bd1e089-480b-0410-8dfb-8563597acbee