cmake check if VTK version is lower than 5, and give fatal error if it is

modules/viz/CMakeLists.txt

@@ -12,9 +12,9 @@ macro(find_qvtk)
 endmacro()
 
 macro(find_vtk)
-  find_package(VTK 5.10.0)
-  if(NOT VTK_FOUND)
-    find_package(VTK 6.0.0 REQUIRED)
+  find_package(VTK)
+  if(${VTK_MAJOR_VERSION} LESS 5)
+    MESSAGE(FATAL_ERROR "VTK 5 or more required!")
   endif()
   if(VTK_FOUND)
     if (BUILD_SHARED_LIBS OR (NOT BUILD_SHARED_LIBS AND NOT VTK_BUILD_SHARED_LIBS))