insert missing #pragma once in VariableTypeUtils.h (#21134)
Summary:
insert missing #pragma once keyword to prevent redefinition error
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21134
Differential Revision: D15607673
Pulled By: li-roy
fbshipit-source-id: 0000fa18e3c55e5d36a64b171d6e85eb4bc211a1
