about vg dataset's dataloader bug

[JackWhite-rwx]

🐛 Bug

First of all, thank you very much for your excellent work! I finds a bug at

https://github.com/KaihuaTang/Scene-Graph-Benchmark.pytorch/blob/45cd54f7465b81d3154e94fcab2b554a09637f6f/maskrcnn_benchmark/data/datasets/visual_genome.py#L87

Although it currently does not affect the normal operation of the code,I think that can be fixed:

target = self.get_groundtruth(index, flip_img=flip_img)

to solve some problem about Parameter Passing in the future.

thanks again.