Summary:
To fix the issue of failing to decompress existing value after reopen DB with a different compression settings.
Closes https://github.com/facebook/rocksdb/pull/3142
Differential Revision: D6267260
Pulled By: yiwu-arbug
fbshipit-source-id: c7cf7f3e33b0cd25520abf4771cdf9180cc02a5f