Summary:
util/ means for lower level libraries, so it's a good idea to move the files which requires knowledge to DB out. Create a file/ and move some files there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5375

Differential Revision: D15550935

Pulled By: siying

fbshipit-source-id: 61a9715dcde5386eebfb43e93f847bba1ae0d3f2