The variable 'cf_opts' is not used by 'DB::open_cf'

[iiibui]

https://github.com/tikv/rust-rocksdb/blob/d8b7ff8aee62aa9a406b64f7093049d62eeb9a1a/tests/cases/test_rocksdb_options.rs#L345-L374

DB::open_cf(opts, path.path().to_str().unwrap(), vec!["default"]).unwrap(); why not DB::open_cf(opts, path.path().to_str().unwrap(), vec![("default", cf_opts)]).unwrap();

[tabokie]

Good catch, feel free to file a fixing PR.

This particular issue could be easily detected by clippy, but there're too many of them and we never get the time to fix them.