Summary:
Added setting of zstd_max_train_bytes compression option parameter to c interop.
rocksdb_options_set_bottommost_compression_options was using bool parameter and thus not exported, updated it to unsigned char and added to c.h as well.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6796
Reviewed By: cheng-chang
Differential Revision: D21611471
Pulled By: ajkr
fbshipit-source-id: caaaf153de934837ad9af283c7f8c025ff0b0cf5
22e5c513c2