Revert "Added "-fopenmp" cflags (#2783) (#3006)" (#3038)
Revert "Added "-fopenmp" cflags (#2783) (#3006)" (#3038)

This reverts commit 74de51d6d478e289135d9274e6af550a9bfba137.
pytorch/vision,pytorch/vision,pytorch/vision,pytorch/vision,pytorch/vision,pytorch/vision