ENH: run the right cmake

Tests/CMakeBuildTest.cmake.in

@@ -38,7 +38,7 @@ if(RESULT)
 endif(RESULT)
 
 # build it again with clean and only COnly target
-execute_process(COMMAND "@CMAKE_CMAKE_COMMAND@" 
+execute_process(COMMAND "${CMAKE_COMMAND}" 
   --build "@CMAKE_BUILD_TEST_BINARY_DIR@" --config Debug 
   --clean --target COnly
   RESULT_VARIABLE RESULT)