Perform exact matching when the prefix "=" is specified in the NCCL_IB_HCA variable to exclude HCAs mlx5_X[0-9]+ when mlx5_X is specified.
Perform exact matching when the prefix "=" is specified in the NCCL_IB_HCA variable to exclude HCAs mlx5_X[0-9]+ when mlx5_X is specified.