minor fix for static build

Former-commit-id: e135cee1ea72a6a3dd02454ebc715f1fb290e5fe

tutorial/cmake/FindNANOGUIH.cmake

@@ -38,9 +38,9 @@ ENDIF (NANOGUI_INCLUDE_DIR)
 if(NANOGUI_FOUND)
   message(STATUS "Found NANOGUI: ${NANOGUI_INCLUDE_DIR} -- HEADERS ONLY")
 else(NANOGUI_FOUND)
-  if (NOT NANOGUI_FIND_QUIETLY)
+  if (NOT NANOGUIH_FIND_QUIETLY)
     message(FATAL_ERROR "could NOT find NANOGUI")
-  endif (NOT NANOGUI_FIND_QUIETLY)
+  endif (NOT NANOGUIH_FIND_QUIETLY)
 endif(NANOGUI_FOUND)
 
 endif(NOT NANOGUI_FOUND)