Redundant Variable in Script gpu_bdb_load_test.py

[K-Wu]

In input conversion script gpu-bdb/gpu_bdb/queries/load_test/gpu_bdb_load_test.py, there is an unused variable scale at line 26. Besides, it makes assumption about the data_dir pattern and may fail when it is not met.

https://github.com/rapidsai/gpu-bdb/blob/main/gpu_bdb/queries/load_test/gpu_bdb_load_test.py#L26

[beckernick]

Thanks for the report @K-Wu ! This may be a leftover from an earlier version. We'll investigate.