opencv3.4.2cmake下载不到的文件包括：vgg_generated_48.ivgg_generated_64.ivgg_generated_80.ivgg_generated_120.iboostdesc_bgm.iboostdesc_bgm_bi.iboostdesc_bgm_hd.iboostdesc_binboost_064.iboostdesc_binboost_128.iboostdesc_binboost_256.iboostdesc_lbgm.i