Summary:
After a successful recovery, the CURRENT file should be updated to point to the valid MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6746

Test Plan: make check

Reviewed By: anand1976

Differential Revision: D21189876

Pulled By: riversand963

fbshipit-source-id: 7537b49988c5c425ebe9505a5cc260de351ad79b